Albert Barnes Commentary Acts 17:2

"and Paul, as his custom was, went in unto them, and for three sabbath days reasoned with them from the Scriptures," — Acts 17:2 (ASV)

His manner was. His custom was to attend the worship of the synagogue and to preach the gospel to his countrymen first, Acts 9:20; 13:5, 14.

Reasoned with them. He discoursed to them, or attempted to prove that Jesus was the Messiah. The word used here (dielegeto) often means no more than to make a public address or discourse. See Barnes on Acts 24:25.

Out of the Scriptures. By many critics this is connected with the following verse, Opening and alleging from the Scriptures, that Christ must needs have suffered, etc. The sense is not materially varied by the change.