Acts 19:3

And he said, Into what then were ye baptized? And they said, Into John's baptism.

Alexander Campbell said that "This indicates that John the Baptist's baptism was not Christian baptism; for in the latter they could not have been baptized without hearing of it."[5] Dummelow concurred in this view, saying that in the apostolic age, "It is probable that the Trinitarian formula was used (in baptizing), Matthew 28:19."[6]

Unto John's baptism ... Wesley was no doubt incorrect in the view that these people "had been formerly baptized by John the Baptist."[7] "They had been baptized by some of John's disciples after the baptism of John had been invalidated."[8] John's baptism lasted only until Pentecost; but the persons who had submitted to it while it was in force were not required to be re-baptized, hence the conclusion that the disciples here were baptized unto John's baptism at a time when it was no longer valid.

As Hervey declared:

Nothing can mark more strongly the connection between baptism and the reception of the Holy Spirit than this question does. For it implies, How could you be ignorant of the giving of the Holy Spirit if you were duly baptized?Acts 2p. 114.">[9]

In New Testament, the reception of the Holy Spirit was made contingent upon the baptism of penitent believers (Acts 2:38f).

[5] Alexander Campbell, Acts of Apostles (Austin, Texas: Firm Foundation Publishing House), p. 126.

[6] J. R. Dummelow, Commentary on the Holy Bible (New York: The Macmillan Company, 1937), p. 845.

[7] John Wesley, New Testament Commentary (Grand Rapids, Michigan: Baker Book House, in loco.

[8] H. Leo Boles, op. cit., p. 299.

Acts 2p. 114.">[9] A. C. Hervey, The Pulpit Commentary, Acts (Grand Rapids, Michigan: Wm. B. Eerdmans, Publishers, 1950), Acts 2p. 114.