2) From chief persecutor (9:1-2) to chief proclaimer: v15, 17-18; 9:20-22; Galatians 1:13-24

3) From law enforcer (take prisoners) to liberator from the Law: vv20-22; Rom 3:28, 7:6, 8:1-39; Gal 2; Php 3:7-9

John F. MacArthur, Jr., Fervency in Speaking

Immediately he began to proclaim Jesus in the synagogues, saying, "He is the Son of God." And all those hearing him continued to be amazed, and were saying, "Is this not he who in Jerusalem destroyed those who called on this name, and who had come here for the purpose of bringing them bound before the chief priests?" But Saul kept increasing in strength and confounding the Jews who lived at Damascus by proving that this Jesus is the Christ. Acts (9:20–22) Those transformed by the saving grace of God cannot stop speaking about it (Acts 4:20), and Saul was no exception. After a few days of fellowship with the saints, he immediately began to proclaim Jesus in the synagogues. To the shocked Christians, surprised by his conversion, can be added the shocked Jews, who were expecting him to take Christians prisoner, not preach Jesus Christ in their synagogues. From the beginning he felt that courageous compulsion that later caused him to exclaim, "Woe is me if I do not preach the gospel" (1 Cor 9:16).

In the very synagogues to which he had come with warrants for the arrest of Christians, Saul now began to proclaim Jesus. The content of that preaching was that Jesus is the Son of God, a title for our Lord that speaks of His deity (cf John 10:31-36). (For a discussion of the issue of the sonship of Jesus Christ, see Hebrews, MacArthur New Testament Commentary [Chicago: Moody, 1983], 26ff)

The shock and consternation Saul’s preaching produced is inconceivable for us. The most zealous defender of Judaism now became the most zealous evangelist for Christianity. Not surprisingly, all those hearing him continued to be amazed, and were saying, "Is this not he who in Jerusalem destroyed those who called on this name, and who had come here for the purpose of bringing them bound before the chief priests?" They could not comprehend the drastic change in Saul.

Far from wilting under the pressure of confusion turning into hostility, Saul kept increasing in strength and confounding the Jews who lived at Damascus by proving that this Jesus is the Christ. Like Stephen before him, he met the Jews in open debate about the deity and messiahship of Jesus. Saving faith "comes from hearing, and hearing by the word of Christ" (Rom 10:17).

That Saul was confounding the Jews in this dialogue should surprise no one. He had the finest education first-century Judaism could offer, and they could not hope to match his knowledge of the Scripture. Once he understood who Jesus was, he had the key that unlocked the whole Old Testament. He was then able to use his vast knowledge of those Scriptures and his Spirit-controlled brilliance, as well as the truth of Jesus’ miracles, words, death, and resurrection, to prove that this Jesus was indeed the long-awaited Messiah.