John Gill Commentary Acts 19:6

"And when Paul had laid his hands upon them, the Holy Spirit came on them; and they spake with tongues, and prophesied." — Acts 19:6 (ASV)

And when Paul had laid his hands upon them: They having been before baptized, not by him, but by John, or one of his disciples, in the name of the Lord Jesus; just as Peter and John laid their hands upon the believing Samaritans, who had been before baptized by Philip, (Acts 8:14–17) and the same extraordinary effects followed:

the Holy Ghost came on them ; in his extraordinary gifts, whose special grace they had before an experience of:

and they spoke with tongues ; with other tongues, or in other languages, which they had never learned, or had been used to, as the disciples did at the day of "Pentecost": and prophesied; preached, having an extraordinary gift at once, of explaining the prophecies of the Old Testament, and also foretold things to come.