John’s baptism was a baptism of repentance “for (i.e. ‘in order to,’ A.K.) the remission of sins
(cf. Mark 1:4; Luke 3:3). The only baptism the apostles had was John’s baptism. John was the
harbinger (forerunner) of the Christ. It was his work to prepare the people for the coming of the Lord, and this preparatory work consisted of (among other things) baptism for the remission of sins. To assume otherwise is to conclude that the apostles were in their sins on the day of Pentecost. Moreover, it is affirmed by the sacred historian, Luke, that those who responded to Peter’s command to repent and be baptized for the remission of sins were by the Lord added “to the church” (KJV) or “unto them” (ASV). One does not add something to nothing. It follows, therefore, that the body of disciples which became the nucleus of the New Testament church on the day of Pentecost consisted of John’s disciples plus those garnered by the Lord and the apostles prior to the day of Pentecost (cf. John 4:1-3). These formed the New Testament church when the Holy Spirit came on that memorable day.
The twelve men who were baptized by Paul in Ephesus were people who had been
baptized “unto John’s baptism” after the inauguration of the new institution and when only the
baptism of the Great Commission (Christ-authorized immersion) was valid (cf. Acts 19:1-7). All
who were baptized prior to the cross when only the baptism of John was available had
acceptable immersions and were not “re-baptized.”