The irony is noticeable in Acts:

9:23 Now after some days had passed, the Jews plotted together to kill him, 9:24 but Saul learned of their plot against him. They were also watching the city gates day and night so that they could kill him. 9:25 But his disciples took him at night and let him down through an opening in the wall by lowering him in a basket.

9:26 When he arrived in Jerusalem, he attempted to associate with the disciples, and they were all afraid of him, because they did not believe that he was a disciple. 9:27 But Barnabas took Saul, brought him to the apostles, and related to them how he had seen the Lord on the road, that the Lord had spoken to him, and how in Damascus he had spoken out boldly in the name of Jesus. 9:28 So he was staying with them, associating openly with them in Jerusalem, speaking out boldly in the name of the Lord. 9:29 He was speaking and debating with the Greek-speaking Jews, but they were trying to kill him. 9:30 When the brothers found out about this, they brought him down to Caesarea and sent him away to Tarsus.

9:31 Then the church throughout Judea, Galilee, and Samaria experienced peace and thus was strengthened. Living in the fear of the Lord and in the encouragement of the Holy Spirit, the church increased in numbers.

We can infer that the opponents of Paul were formerly his companions; the same zealous devotees to the Pharisaic interpretation of the Torah were not the opponents of Paul. He escapes Damascus and heads for Jerusalem where he encounters those who are wary of his story of faith.

But Barnabas had the courage to listen to Paul, become convinced Paul’s story was genuine, and then tell the disciples that this Paul was now on their side. Barnabas gives Paul the opportunity to become an advocate of Christ in Jerusalem, but the Greek-speaking (Hellenistic) Jews were opposed to Paul — and no doubt because he believed a crucified man was Messiah, because he was saying things about Christ that were borderline blasphemous (in their one-God view), and he was calling into question the stability of the Jewish community. 

Opposition means Paul has to be secreted away again.

Then the church experienced peace.