Acts 19:4

4. Baptism of repentance John’s baptism when received obligated the people to repent anew of sin in expectation of a soon-coming Messiah. By accepting the rite they acknowledged the obligation and the expectation. Yet when Messiah came he required a new baptism, obligating a consecration to him, whereby the Spirit of promise would be poured out upon them, and they be emancipated into the full liberty of the sons of God.

Christ Jesus Messiah Jesus. John’s baptism obligated faith in the Messiah; John’s testimony obligated faith in Jesus as Messiah. (See notes on John 1:19-42.) The Gospel of the apostle John, indeed, written by him at this same Ephesus, clearly indicates in its first chapter the need, from the great number of Johnites in that locality, of a clear testimony that the Baptist himself did most explicitly affirm Jesus to be the Messiah.