17:2 reasoned with them. Paul was surely one of the most effective witnesses for the Lord who ever lived, so his “manner” of witnessing is highly instructive. His manner in the Thessalonian synagogue is said to have been typical, “[reasoning] with them out of the Scriptures.” This is more, however, than just reading or quoting a set of proof-texts. Such reasoning requires logical argumentation, graciously presented, based on thorough study of the Word (I Peter 3:15; II Timothy 2:15; Colossians 4:6). This was all in the context, also, of full belief in the divine authority of the Scriptures, on the part of both speakers and hearers. The audience in the synagogue already believed in God the Creator and in the absolute truth of Scripture, so Paul could proceed from that foundation.
17:3 from the dead. Since the congregation in the synagogue already believed the Scriptures, Paul could proceed to use the Scriptures to prove that the promised Messiah must die and rise again, and then that Jesus was, indeed, the promised Messiah, using the strong evidence of fulfilled prophecy and the historical bodily resurrection. This can be a general pattern for leading to Christ those people who already believe in the God of creation and His inspired word. For those who are hostile or skeptical, however, a different approach is needed. The two recorded cases when Paul preached to pagans indicate this. See notes on Acts 14:8-18 and Acts 17:15-34.