Acts 9:20. At once he began to preach in the synagogues that Jesus is the Son of God.
How much significance should be placed on this point that Paul immediately began to preach in the synagogues that Jesus is the Son of God? First, consider the evidence that came out at the trial of Jesus Christ.
John 19:5-7. Then came Jesus forth, wearing the crown of thorns, and the purple robe. And Pilate said unto them, Behold the man! When the chief priests therefore and officers saw him, they cried out, saying, Crucify him, crucify him.
Pilate said unto them, you take him, and crucify him: for I find no fault in him. The Jews answered him, We have a law, and by our law he ought to die, because he made himself the Son of God.
At a public trial, the testimony of His accusers was that Jesus must die for claiming to be the Son of God. Now the man who was previously persecuting the church, one of high esteem among the religious leadership, was preaching this very thing! This is an extraordinary turn of events, that the one who was identified and accepted by the original disciples as the “apostle to the gentiles”, would first boldly preach in the synagogues of every place he visited.
For many have come before and after claiming to be a messiah, a fact of which has often been attested. For messianic Jews to simply proclaim Yeshua haMashiach in Israel or anywhere in the world is nothing new under the sun. If you want to stir up the status quo, preach the Son of God.
Acts 5:34-39. Then stood there up one in the council, a Pharisee, named Gamaliel, a doctor of the law, had in reputation among all the people, and commanded to put the apostles forth a little space; And said unto them, Ye men of Israel, take heed to yourselves what ye intend to do as touching these men. For before these days rose up Theudas, boasting himself to be somebody; to whom a number of men, about four hundred, joined , who was slain; and all, as many as obeyed him, were scattered, and brought to nought. After this man rose up Judas of Galilee in the days of the taxing, and drew away much people after him: he also perished; and all, even as many as obeyed him, were dispersed. And now I say unto you, Refrain from these men, and let them alone: for if this counsel or this work be of men, it will come to nought: But if it be of God, ye cannot overthrow it; lest haply ye be found even to fight against God.
It is noteworthy that this same Gamaliel was the headmaster of the school of the Pharisees where Saul trained. And who was the one man that disregarded this advice and set off on a murderous rampage against the church? Irony!
Before appearing at the judgment seat of Pilate, Jesus was examined by the High Priest, along with the scribes and elders. Many false witnesses came forward to accuse Jesus, but none of the charges held. Then the High Priest played his trump card:
Matthew 26:63-66. But Jesus held his peace. And the high priest answered and said unto him, I adjure thee by the living God, that thou tell us whether thou be the Christ, the Son of God. Jesus saith unto him, Thou hast said: nevertheless I say unto you, Hereafter shall ye see the Son of man sitting on the right hand of power, and coming in the clouds of heaven. Then the high priest rent his clothes, saying, He hath spoken blasphemy; what further need have we of witnesses? behold, now ye have heard his blasphemy. What think ye? They answered and said, He is guilty of death.
And so the religious authorities found Jesus guilty of blasphemy and worthy of death for claiming to be the Son of God. Then Saul, upon his conversion immediately preached this in the synagogues, thereby, bringing the same charge against himself. Then he gave this testimony of himself before his conversion.
1 Tim 1:13. Who was before a blasphemer, and a persecutor, and injurious: but I obtained mercy, because I did it ignorantly in unbelief.
This is his conversion, to embrace what was called blasphemy, and reject what was before:
Acts 22:3. I am verily a man which am a Jew, born in Tarsus, a city in Cilicia, yet brought up in this city at the feet of Gamaliel, and taught according to the perfect manner of the law of the fathers, and was zealous toward God, as ye all are this day.
The Lord Jesus Christ expects us to preach His Blasphemy, for this is the most excellent glory that He received:
2 Peter 1:17. For he received from God the Father honor and glory, when there came such a voice to him from the excellent glory, This is my beloved Son, in whom I am well pleased.
John 10:36. Do you say of Him whom the Father sanctified and sent into the world, ‘You are blaspheming,’ because I said, ‘I am the Son of God’?