New Defender's Study Bible Notes
19:2 since. A better rendering of this phrase would be “when ye believed.”
19:2 believed. These twelve Ephesian disciples were evidently considered disciples of Christ, rather than of John, since Paul recognized they had “believed.” Also, they would surely have been identified specifically as disciples of John had that been the case (compare John 3:22-26). John had, of course, preached that Jesus was the promised Redeemer and the Lamb of God. In some way, possibly through some of John’s disciples rather than John himself, they had learned of Jesus and had believed on Him. What they had learned, however, did not include the coming of the Holy Spirit on the day of Pentecost, and so was deficient, even though it had been enough to bring them salvation. In fact, John himself had been given the authority “to give knowledge of salvation unto His people by the remission of their sins” (Luke 1:77).
19:2 not so much as heard. This admission proves that the Ephesian disciples had not heard the message of John directly, since John had certainly preached about the Holy Spirit (e.g., Matthew 3:11; John 1:32-34) and was himself “filled with the Holy Ghost” (Luke 1:15).