The next use of a “repentance” word in Acts is in Acts 19:4. In this passage, though the word is used, the behavioral content of repentance is not directly in view:
1 While Apollos was at Corinth, Paul, having passed through the upper country, came to Ephesus, and found certain disciples. 2 He said to them, “Did you receive the Holy Spirit when you believed?” They said to him, “No, we haven’t even heard that there is a Holy Spirit.” 3 He said, “Into what then were you baptized?” They said, “Into John’s baptism.” 4 Paul said, “John indeed baptized with the baptism of repentance (metanoias), saying to the people that they should believe in the one who would come after him, that is, in Jesus.” 5 When they heard this, they were baptized in the name of the Lord Jesus. Acts 19:1-5 (WEB).
On the one hand, John told the people he baptized that they should believe in the one who came after him, Jesus. This is the central focus of this passage. These disciples of John the Baptist were told of Jesus, believed and were baptized. On the other hand, Paul clearly tells them that John’s baptism was a “baptism of repentance.” While this is not the focus of the passage, it accurately references the central message of John—that they must repent, because the Kingdom, represented by the King Himself, was near. As has been shown in a previous post, when John told the people to repent, he very much had in mind changed behavior, and a changed way of life.