Original Research

A critical study of Pentecostal understanding of the baptism of the Holy Spirit in Acts

Kalis Stevanus, Ivan Th. J. Weismann, Christopher J. Luthy, Daniel Ronda, Randy F. Rouw

Received: 14 Sept. 2022; Accepted: 03 Jan. 2023; Published: 27 Feb. 2023

Copyright: © 2023. The Author(s). Licensee: AOSIS.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In faith and practice, Pentecostals put emphasis on practical issues as well as spiritual experience in their theological understanding and doctrinal teachings. The Pentecostals take their doctrine from certain empirical events. One of the spiritual experiences often underlined is the baptism of the Holy Spirit. In interpreting the Book of Acts, Pentecostals tend to emphasise the theological character of the narratives and seldom their historical uniqueness. That is why Pentecostals stress the normative theological intent of the historical record for contemporary Christian experience. This article therefore examines critically Pentecostal paradigm of the baptism of the Holy Spirit, deriving examples from the Acts of the Apostles. It is concluded that the practice of the baptism of the Holy Spirit carried out by Christians today, arguably, has no biblical basis. This is because, there is nowhere the Bible commands people to seek baptism in the Holy Spirit. The observation is that, all the events or experiences of Christians baptised in the Holy Spirit in Acts are not necessarily universal normative for every Christian and for this reason, there is no need to be dogmatic.

Contribution: This article challenges the practice of the baptism of the Holy Spirit in church today. This study supports the fact that the baptism of the Holy Spirit is not a universal experience for every Christians and there is no need to be dogmatised.

Keywords: Pentecostals; baptism of the Holy Spirit; Acts; Pneuma; glossolalia.

Introduction

Pentecostalism, as a Christian religious movement, has received much attention from historians, sociologists and theologians. However, little attention has been given to the development or thought of Pentecostal theology (Archer 2007:301) and this makes this article important with regard to scholarship. One of the teachings, also emphasised as a characteristic of Pentecostal tradition, is the doctrine of being baptised in the Spirit (Lewis 2010:301; Tupamahu 2007:246). The baptism of the Holy Spirit is missiological in nature, so it becomes a tool of effective witness-ministry (Stevanus & Panjaitan 2021:19). Menzies (2015:36), a Pentecostal theologian from the Assemblies of God, defines Pentecostalism as a Christian movement that believes in the apostles’ experience to provide a ‘model’ for churches. The other defining tenet is that baptism in the Spirit as the giving of ‘power’ for effective witnessing is confirmed by the physical sign of speaking in tongues.

In general, glossolalia is used as the theological basis in Pentecostal churches in their faith and practice. Most neo-Pentecostal churches misrepresent and overestimate glossolalia. The author under observation found several churches or synods in Indonesia with Pentecostal beliefs such as Assemblies of God Church, Pentecostal Church in Indonesia, Pentecostal Missionary Church, Full Gospel Bethel Church, Indonesian Rehoboth Church, Good God Church, Indonesian Bethel Church, etc. Koech (2005) says that the view of glossolalia had become a point of debate and even contention among Christians. Some of those churches think speaking in tongues is the main gift, so it must be experienced. Sometimes there is an attitude of branding those who do not have it as ‘less spiritual’ and churches are even divided over this issue. To this end of time, leadership in the church is sometimes measured by ownership of this phenomenon (Koech 2005:25).

What this means is that there is still much confusion surrounding the doctrine of being baptised in the Spirit and glossolalia. The differences in these teachings often lead to secessionism among Pentecostals. This article therefore carries out a hermeneutic review of the Pentecostal perspective on being baptised in the Holy Spirit. The idea is to interrogate whether the fundamental teaching of being baptised in the Spirit is biblical, consistent and in sync with the teachings of other New Testament books using Pentecostal theology as a case in point.

Method

The critical historical method is used as hermeneutical lens (Kinsella 2006:1). The idea is to the essence and message of the Book of Acts from a historical perspective and unravel the background of the author. Through historical studies, contemporary readers can obtain the meaning of the text, the aims and objectives of the text, as well as theological reflections on its relevance at today.

The baptism in the Holy Spirit at Pentecost as the birth of the church

The Day of Pentecost was a confirmation of what Jesus had promised: the coming of the baptism of the Spirit! (The Pentecost event, however did not mention specifically the term Spirit baptism; read Ac 2:1–13). The Pentecost event is a unique event – the day the church was born (Ac 2:17–18). Santoso asserts that the outpouring of the Holy Spirit on the day of Pentecost was the Christian church’s birthday, or in other words, the end times, and dawn of a new era (Santoso 2010:129). In Bruce’s opinion (1988:130) there is a need to improve on this again; the outpouring of the Holy Spirit at Pentecost is associated with the inauguration of the new age. This explains why Witherington (1998:132) reaffirmed that the Pentecost event was unique and could not be repeated.

From a Christian perspective, the Pentecost is the church’s birth in which the Holy Spirit remains in believers in Jesus (Ac 2:13). The baptism of the Holy Spirit is the church in nature. What this means by ‘status’ [de jure], every believer in Christ has been baptised in the Holy Spirit on Pentecost. However, by ‘personal experience’ [de facto], a person is baptised in the Holy Spirit at the time of his conversion to accept Jesus. It is like the Lord Jesus ‘baptised him with the Holy Spirit’. At that moment, he became the member of the body of Christ.

Jesus as the seal of Spirit baptism

The meaning of being ‘baptised with the Holy Spirit’ in Acts 1:5 and chapter 11:16 is βαπτισθήσεσθε ἐν πνεύματι ἁγίῳ in the Greek text.

It becomes evident again when it says: ‘And received the promised Holy Spirit’ in the Greek text τήν τε ἐπαγγελίαν τοῦ πνεύματος τοῦ ἁγίου λαβὼν παρὰ τοῦ πατρός, meaning [‘and received the promise of the Holy Spirit from the Father]’. So this means that Jesus received ‘the promise’ from the Father and: ‘So He poured out’ verb (ἐξέχεεν [verb indicative aorist active] of ἐκχέω) ‘he poured out’. According to the context here, the Lord Jesus does the outpouring of the Holy Spirit, not the Holy Spirit who baptises.

The phrase ‘Baptised in the Holy Spirit’ is a future passive indicative referring to the person of Jesus. The preposition ἐν means [inside, with, as an instrument]. Jesus will baptise with the Holy Spirit (ἐν πνεύματι βαπτισθήσεσθε ἁγίῳ). The preposition ἓν means [in] the Holy Spirit. Grammatically, the ἓν that relates to baptising is never used to refer to the baptist but always refers to the element of baptism. So it is arguable that what is meant by being baptised by the Holy Spirit: not the Holy Spirit who does the baptism but through the Holy Spirit. Therefore, three things are emphasised here, namely

• The subject: the one who baptises is Jesus
• The object: the disciples are baptised
• The instrument or element of baptism is the Holy Spirit.

It becomes apparent when the Lord Jesus begins his office as a baptiser with the Holy Spirit. It turns out that this was done not at the beginning of his earthly ministry but after completing his ministry as the holy and glorified One. Acts 2:33 reads, ‘And when he was lifted by the right hand of God and received the promised Holy Spirit, he poured out what you have seen and heard here.’ Who is he that is meant here? Peter refers only to Jesus, not another person: ‘He was exalted by the right hand of God’ ῇ δεξιᾷ οὖν τοῦ θεοῦ ὑψωθείς. The ‘right hand’ is an anthropomorphic description of a place of power or authority quoted from Psalm 110:1. It seems that this is indeed what is meant, considering the expression ‘to sit […] on his throne’ (v. 30). This appears to be related to the place of the seat, namely ‘to the right’. This (anthropomorphic) expression is a metaphor, which means giving a position full of rights, power and authority. These words are intended to pass a paradigm or concept regarding the divinity of Jesus. Here, Peter interprets the connection between Jesus’ glorification and resurrection and his coronation as Messianic (Ac 2:25, 30–36). That’s why Keener (2012) says that Peter interprets the ascension of Jesus in the light of Psalm 110:1 and Jesus is the ‘Glorified Lord’. It is he who pours out the Holy Spirit and not the other people.

The baptism of the Holy Spirit occurs concurrently with new-birth conversions

The baptism of the Holy Spirit occurs at the same time as new-birth conversions. In Acts 2:38, Peter answered the crowd: ‘[…] repent’ (μετανοήσατε) meaning [‘change one’s mind]’. Because in this context, sin is associated with the attitude of rejecting or not acknowledging Jesus as Lord (κύριος). Peter offers the hope of forgiveness of sins and receiving the gift of the Holy Spirit for those who confess Jesus as Lord and Saviour (Ac 2:31, 36). John 3:8 affirms the Holy Spirit. Indeed, in the previous text this passage refers to the baptism in the Spirit (Luthy 2020:117). Thus, baptism in the Holy Spirit reaffirmed that everyone must be born of the Spirit.

Stott (1975:96) asserts that God’s statement through the apostle Peter in Acts 2:38 is a sure guarantee that receiving the gift of the Holy Spirit coincides when people repent and believe in the Lord Jesus. So, repentance is essential to receive forgiveness of sins and the gift of the Holy Spirit. When a person repents, then at that time, he or she also receives the gift of the Holy Spirit and the forgiveness of sins. The new birth occurs when a person repents. This means that when a person believes, repents and accepts Jesus as Lord and Saviour, and he or she is immediately baptised with the Holy Spirit. Therefore, the baptism of the Holy Spirit is not a spiritual experience to be sought after [second blessing] after conversion. In addition, there is not a single verse in the New Testament that commands Christians to seek the experience of the baptism of the Holy Spirit. Stott (1975) emphasises that the baptism of the Spirit does not need to wait anymore or look for it because it has been accepted by Christians when they repent and believe in Christ.

At Cornelius’ house, it was evident that the gift of speaking in tongues and the gift of prophecy were associated with the time of conversion not as a second post-conversion experience. They receive the Holy Spirit at conversion. However, it is interesting that Peter said that the experience of Cornelius’ family was ‘just as it was upon us’. This statement is repeated twice in verse 17. The promise of the baptism of the Holy Spirit when Cornelius and his family became believers instantly were baptised in the Holy Spirit. The baptism of the Holy Spirit takes place at the time of repentance being born-again. There is no period between the new birth (renewal) and the baptism of the Spirit. Precisely through the coming of the Holy Spirit and the baptism of the Holy Spirit, the unbelievers, namely Cornelius and his friends, became Christians. There is no separation between ‘baptism of the Holy Spirit’ and repentance, that is having ‘faith in Jesus’ [repentance]. This is seen through the attitude of Peter, and the elders in Jerusalem, who concluded, based on the gift of the Holy Spirit to the unbelievers, that they had become believers (Ac 11:17) and had received eternal life on the basis of repentance (Ac 11:17, 11:18).

To this end, the conclusion is that the baptism of the Holy Spirit is ‘inseparable’ from regeneration and repentance. The Book of Acts always reports that the Holy Spirit was received simultaneously on ‘believing’. There is no teaching in the book of Acts of the Apostles and apostolic letters that separates the baptism of the Holy Spirit from the work of the Holy Spirit on repentance and new birth of a believer.

Spirit baptism is synonymous with salvific experience

The disciples of Jesus by being outpoured by the Holy Spirit on Pentecost had been born again or saved. The baptism of the Holy Spirit on the day of Pentecost is therefore a milestone in the history of salvation [soteriology] because it is the Holy Spirit who can apply the work of the Lord Jesus in the lives of believers.

The baptism of the Holy Spirit, which the Lord Jesus promised in Acts 1:5 for his disciples before his ascension to Heaven, had occurred and was fulfilled by pouring out the Holy Spirit on the day of Pentecost (Ac 2). All believers experience the baptism of the Holy Spirit. That is the only baptism of the Holy Spirit for all believers, which the Lord Jesus Himself has performed as the Baptist (Ac 2:33). Baptism with the Holy Spirit is the authority of the Lord Jesus himself! Being baptised in the Holy Spirit is God’s act, which is the foundation and beginning of the Christian life. For this reason, the baptism of the Holy Spirit cannot be separated from believing in Christ. Salvation and the baptism of the Holy Spirit occur together because a person cannot be saved without the work of the Holy Spirit. Walvoord (2010:5) also concludes that they were saved and baptised with the Holy Spirit when they believed. A person cannot be saved without the work of the Holy Spirit. So being saved and baptised in the Holy Spirit is the same experience.

The baptism of the Holy Spirit is God’s work ‘as soon as’ people become believers. After investigating the terms used by Luke in the Acts of the Apostles on the baptism of the Holy Spirit, six phrases about the Pentecost event have similarities with the events at Cornelius’ house (Ac 11): Acts 10:45 ‘the gift of the Spirit the Holy was poured out’; Acts 10:47 ‘received the Holy Spirit’; Acts 11:15 ‘the Holy Spirit came down’; Acts 11:16 ‘baptised with the Holy Spirit’; Acts 11:17 ‘given His gift (Holy Spirit)’; Acts 11:17 ‘believed’. The six terms are synonyms where they all relate to the same event. In other words, ‘became believers’, received the Holy Spirit, and ‘baptised with the Holy Spirit’ emphasises different aspects of ‘one event’, namely the event of people becoming believers. This also applies to the other two phrases about the Pentecost that only appear in Acts 2: ‘being filled with the Holy Spirit’ (Ac 2:4), and ‘pouring out the Holy Spirit’ (Ac 2:17, 18, 33). Among the six verses where the expression ‘baptised in the Holy Spirit’ occurs (Ac 1:5; 11:16; cf. Mt 3:11; Mk 1:8; Lk 3:16; Jn 1:33), it is explicit that none of these verses defines being baptised in the Holy Spirit as the second coming of the Holy Spirit after conversion as new birth or being saved.

Although many different terms are used in the Book of Acts for the coming of the Holy Spirit, it does not mean that every other term refers to a different experience. On the other hand, these terms regarding the arrival of the Holy Spirit only designate various aspects of such a broad ‘single event’, namely what the Holy Spirit does at the time of the new birth. The baptism of the Holy Spirit applies universally to all believers. In the Book of Acts and other parts of the New Testament (e.g. Gl 3:2, 5, 15; Eph 1:13), it is clearly stated that to believe, being born again and receiving the Holy Spirit always occur at the same time. As the baptism of the Holy Spirit occurs at the time of the new birth, the Bible does not tell Christians to seek it. Supposing that the baptism of the Holy Spirit is the second blessing as an essential step in the Christian life. To one’s surprises, neither the Book of Acts nor any New Testament book mentioned a single verse that indicates that baptism in the Holy Spirit is something to be sought, as what Pentecostals teach.

On the other hand, the apostles speak of being filled with the Holy Spirit, not to be baptised in the Holy Spirit. To separate the baptism of the Holy Spirit from the experience of being born again and saved clearly has no biblical basis. The commandment to ‘wait’ for the baptism of the Holy Spirit in Jerusalem ‘only applies’ to the disciples of the Lord Jesus at that time and does not apply to believers today. The experience of the Lord Jesus’ disciples in Jerusalem cannot be a model or normative for the experience of later believers seeking the baptism of the Holy Spirit. The church is commanded to baptize those who believe in water baptism (Ac 2:38; cf. Mt. 28:19–20) because the experience of being saved is a single event, not two separate and distinct events.

Being baptised by the Holy Spirit and being filled with the Holy Spirit

Acts 2:4 says: ‘Then they were filled with the Holy Spirit.’ In this text, a ‘then’ is conjunction. This implies that what is said in this verse is an event that happened simultaneously at that time. It can be translated as ‘at that very moment’. What this means is that ‘the filling of the Holy Spirit’ does not come sometime later but immediately occurs or is experienced when they are baptised in the Holy Spirit.

There is something that needs serious attention in this verse. In the Indonesian translation, there is an incomplete word, which should have the word ‘all’ (πάντες). In English translations such as KJV, NAS, NIV, NKJ and SRV, there is an emphasis on the word ‘all’. Receive the fullness of the Spirit and be filled with the Holy Spirit at that time. On the day of Pentecost, the disciples experienced the baptism of the Holy Spirit, and at the same time, they were filled with the Holy Spirit. The terms ‘baptism in the Holy Spirit’ and ‘being filled with the Holy Spirit’ are used interchangeably without any difference in meaning. The author agrees with Dunn (2016:49) who says that the Pentecost event was a baptism of the Spirit and fulfilling the Holy Spirit on the disciples.

The Lord promised his disciples that they would ‘be baptised with the Holy Spirit’ (Ac 1:5; 11:16). The term ‘baptised with the Holy Spirit’ in the Greek text is ἐν πνεύματι βαπτισθήσεσθε ἁγίῳ. In this context ‘baptism’ (indicative verb future passive) means that the event will happen in the future. But in essence, the baptism of the Holy Spirit only occurs once (not to be repeated). This statement is confirmed by other parts of the New Testament, especially the teachings of Paul. In 1 Corinthians 12:13 baptised translated as ἐβαπτίσθημεν is verb indicative of aorist passive. Paul does not use the future or imperative form, as reported in Acts 1:5 and 11:16. Instead, Paul uses the past participle tense (or the aorist form), indicating that it has already happened, is complete and is not repeated. The word ἐβαπτίσθημεν being baptised, thus means that the baptism of the Holy Spirit has occurred in the Christian’s life, and this event will not be repeated.

The Acts of the Apostles has a record of the testimony of the repeated filling of the Holy Spirit. On the day of Pentecost (Ac 2:4), the disciples (with Peter) were filled with the Holy Spirit (ἐπλήσθησαν ἅπαντες πνεύματος ἁγίου). In this text [full] is written as ἐπλήσθησαν from the πίμπλημι. It means the people who experienced the infilling of the Holy Spirit more than once were Peter and Paul. On the other hand, the Greek πλησθεὶς comes from the root πίμπλημι. It is grammatically precise that being filled with the Holy Spirit can happen again and again. This conclusion is confirmed by what Paul teaches in Ephesians 5:18: ‘be full of the Spirit’ (πληροῦσθε ἐν πνεύματι). This is because πληροῦσθε is a form of imperative present passive from the word πληρόω, indicating the existence of an order that must occur continuously and more than once.

The baptism of the Holy Spirit is enough to be received by faith without having to confirm the gift of tongues

In Acts, there are four events of the descent of the Holy Spirit, in (Ac 2). Acts 1:3–8 reveals the promise of the Lord Jesus before ascending to Heaven. When the disciples were forbidden to leave Jerusalem, they obeyed and did not leave the city. They gathered somewhere and then prayed. The apostles were there too. In addition, there were several women, one of whom was Mary: the mother of Jesus. A total of 120 people gathered there. After waiting for 10 days, the Holy Spirit came upon them. This event was the first time the world received the Holy Spirit. As Luke reports (Ac 2:1–4), the coming of the Holy Spirit could be heard, for people could hear a sound like the rushing of a mighty wind. Also can be seen/witnessed directly as visible tongues like flames. In addition, it is also accompanied by tongues, λαλεῖν ἑτέραις γλώσσαις (v. 4).

Pentecostals in general (in the neo-Pentecostals, but not in the classical Pentecostals), still insist that the experience of being baptised in the Holy Spirit must be confirmed, especially in tongues. In the entire record of Acts itself, there is no indication that explicitly states speaking in tongues as a sign of being baptised in the Holy Spirit. A total of 120 people received the Holy Spirit (baptised by the Holy Spirit) and experienced being filled with the Holy Spirit (v. 4). However, only the apostles were given the gift of tongues because verse 7 says: ‘The crowds […] were confused because each of them heard the apostles speaking in their language.’ The apostles were given tongues to witness the great deeds that the Lord had performed (v. 11). All the disciples were called to be his witnesses. A total of 120 people were not speaking in tongues.

The outpouring of the Holy Spirit in the Acts of the Apostles

On the day of Pentecost, the Holy Spirit came in two stages. Firstly, the Holy Spirit descended upon the 120 disciples of Jesus who had waited for 10 days in Jerusalem. Secondly, the Holy Spirit descended on 3 000 people. Who was converted because of the preaching of the gospel by the apostles on the day of Pentecost (Ac 2:41-42)? Again, there is no record whatsoever that the 3 000 believers spoke in tongues. They have repented and have accepted the Lord Jesus. However, these 3 000 also received the gift of the Holy Spirit. They were baptised in the Holy Spirit after being repented and believed, without needing to wait for any longer (Ac 2:38–39). Peter stated that the forgiveness of sins and the gift of the Holy Spirit are received at the same time. According to Nel (2021:6), the role of the Holy Spirit throughout the ages has also influenced the interpretive process of reformers and Pentecostals in theology and building church doctrine.

The first event is in Acts 8:14–17 in which the Holy Spirit descended upon the repentant Samaritans. There is no record of the existence of tongues here. The third event is in the love of the Apostles 10:44–46; the Holy Spirit descends on the Gentiles pagans. For the first time in history, the Holy Spirit descended on an uncircumcised person. That is why Peter was astonished to see them receive the Holy Spirit. The Jews who knew and experienced the events in Jerusalem were astonished because they saw what happened at Cornelius house exactly as it did in Jerusalem. In this event, there is a manifestation of tongues. The fourth event is in Acts 19:1–7; the Holy Spirit descended on the disciples of John the Baptist. When Paul preached the gospel and laid hands on them, the Holy Spirit fell on them, and they began to speak in tongues and prophesy. There were about 12 people in number. Here Paul does not talk of ‘baptism of the Holy Spirit’. He said they must believe in the One who came later from John the Baptist meaning Jesus. So, they laid hands and were baptised in the name of the Lord Jesus. At that time, the Holy Spirit came upon them, giving them the gift of tongues and prophecy. It should be observed here that there is no mention of the descent of the Holy Spirit in the Acts of the Apostles after this event.

Based on a comprehensive study of the four events of the descent of the Holy Spirit in the Acts of the Apostles, it is concluded that the reception of the Holy Spirit is ‘not absolute’. There is a phenomenon of tongues, prophecy and other physical signs. The four events of the descent of the Holy Spirit include two groups, namely the Jews and the Gentiles. So, the occurrence of the four events recorded by Luke here is a ‘representation’ of the stages of preaching the gospel in church history, starting from Jerusalem, Judea and Samaria and to the ends of the earth (Ac 1:8). Toussaint (2015:183) think that speaking in tongues is recorded in Acts 2. The baptism of the Holy Spirit occurred simultaneously, but this ‘does not mean’ speaking in tongues is evidence that should mark the baptism of the Holy Spirit. It means the manifestation of glossolalia in the events on the day of Pentecost as a unique and special event/experience, as an ‘exception’.

Walston (2003:151) states that contemporary interpreters must carefully develop doctrinal positions from historical narratives. According to him, historical narratives, such as the Book of Acts, only show the reader what happened to other people in that historical event. Luke indeed wrote the Book of Acts under the inspiration of the Holy Spirit, but that does not make Luke’s writing prescriptive or didactic. The historical narrative of the Book of Acts does not seem to significantly convey the idea that glossolalia is the norm for the baptism of the Holy Spirit.

Conclusion

The Pentecostals state that there is no record of the occurrence of glossolalia in the Acts of the Apostles. It does not mean that glossolalia did not occur. Pentecostals still assume that glossolalia was practised even though it is not written down in Acts. This is also recognized by Pentecostal figures and theologians such as Robert P. Menzies, who is a Pentecostal missionary and scholar who is also known as a proficient Pentecostal apologist from the American Assemblies of God, stating that Pentecostal people always read the narrative of the Acts of the Apostles, and especially the story of the outpouring of the Holy Spirit at Pentecost (Ac 2) as a model for life experiences for the church today. This is confirmed and taught by the Assemblies of God to this day. However, textually this assumption is fragile and inconclusive. A study of the text in Acts has shown evidence that glossolalia is not an experience for every Christian. The view that assumes glossolalia as an initial sign that must accompany the recipient of the baptism of the Holy Spirit does not have a solid theological basis. Arguably, it is a forced exegesis (interpreting the Bible based on experience, not experience based on the Bible). Teaching a doctrine based solely on personal experience, however valid and valuable it may be to the person concerned, is still an act that will cause problems and has certain implications for Christians.

Acknowledgements

The authors would like to acknowledge Sekolah Tinggi Teologi Tawangmangu and Sekolah Tinggi Filsafat Jaffray Makassar who supported the publication of this article.

The authors have declared that no competing interest exists.

The authors, K.S., D.R.,R.F.R., declare that this article is a collaboration between the authors and the supervisors, C.J.L., I.Th.W. and the two institutions.

This article followed all ethical standards for research without direct contact with human or animal subjects.

This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

Data sharing is not applicable to this article as no new data were created or analysed in this study.

The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of any affiliated agency of the author.

References