4 Then said Paul, John verily baptized with the baptism of repentance, saying unto the people, that they should believe on him which should come after him, that is, on Christ Jesus.
English Standard Version
4 And Paul said, "John baptized with the baptism of repentance, telling the people to believe in the one who was to come after him, that is, Jesus."
4 "That explains it," said Paul. "John preached a baptism of radical life-change so that people would be ready to receive the One coming after him, who turned out to be Jesus. If you've been baptized in John's baptism, you're ready now for the real thing, for Jesus."
New King James Version
4 Then Paul said, "John indeed baptized with a baptism of repentance, saying to the people that they should believe on Him who would come after him, that is, on Christ Jesus."
New Living Translation
4 Paul said, "John's baptism called for repentance from sin. But John himself told the people to believe in the one who would come later, meaning Jesus."
Paul, at Ephesus, found some religious persons, who looked to Jesus as the Messiah. They had not been led to expect the miraculous powers of the Holy Ghost, nor were they informed that the gospel was especially the ministration of the Spirit. But they spake as ready to welcome the notice of it. Paul shows them that John never design that those he baptized should rest there, but told them that they should believe on Him who should come after him, that is, on Christ Jesus. They thankfully accepted the discovery, and were baptized in the name of the Lord Jesus. The Holy Ghost came upon them in a surprising, overpowering manner; they spake with tongues, and prophesied, as the apostles and the first Gentile coverts did. Though we do not now expect miraculous powers, yet all who profess to be disciples of Christ, should be called on to examine whether they have received the seal of the Holy Ghost, in his sanctifying influences, to the sincerity of their faith. Many seem not to have heard that there is a Holy Ghost, and many deem all that is spoken concerning his graces and comforts, to be delusion. Of such it may properly be inquired, "Unto what, then, were ye baptized?" for they evidently know not the meaning of that outward sign on which they place great dependence.