The Jews in Damascus recognise that there was a group among them who called on the name of Jesus in prayer. The people of the Way (Christians) invoked the name of Jesus in worship, calling on him as they call on the Lord (see Acts 9:14).1 They are surprised to find that Saul is now also one of their number, especially given the fact that he came to Damascus to arrest the people who belonged to this group.
21 And all who heard him were amazed and said, “Is not this the man who made havoc in Jerusalem of those who called upon this name? And has he not come here for this purpose, to bring them bound before the chief priests?”