Saul's Early Ministry - Damascus

The persecutor becomes the persecuted. Saul's early ministry, according to Luke, has two parts. First, he spent three years in Damascus before he returned to Jerusalem (Galatians 1). Immediately after Saul met Jesus on the road to Damascus, he continued with his original intention—to visit the synagogues—but not with his original purpose—to persecute the followers of Jesus. Luke informs us that Saul reasoned with the Jews concerning the fact that Jesus was the Son of God.

All new Christians need to be discipled. Saul's understanding of who Jesus was had to be learned and cultivated into his life. How did he arrive at the conclusion that Jesus, as Messiah, was also the Son of God? The Jews were expecting the Messiah, but they did not believe that He was divine, the Son of God. That fact is not specifically taught in the Old Testament. It is implied in (1) the Davidic Covenant (2 Samuel 7:12-16); (2) the promised Immanuel (Isaiah 9:1-7); and the Servant of Yahweh (Isaiah 59:15-20; cf. 40:1-9).
We must not discount Saul's own understanding of Jesus' claims. He was accused of blasphemy by the Jews on that very claim (Matthew 26:63-65).

Paul's claim that he did not get his gospel from men (Galatians 1:11, 12) is understood by some commentators as some special schooling that Jesus gave Paul in the Arabian dessert. That would give Paul singular advantage over others, which would place him in a unique privileged position. That interpretation is not necessary. Paul got his understanding in the same fashion that all believers can—by the Holy Spirit guiding him into all truth as revealed in Scripture (John 14:26).