Acts 9:28

And he was with them coming in and going out at Jerusalem.

This brief statement belongs to Paul's visit to Jerusalem shortly after his conversion, after his arrival there and before the work at Lydda and at nearby Joppa where Dorcas lived. He had come wanting to know the apostles, especially Peter, and longing to meet the disciples who had lived and spoken with Jesus. The disciples at first feared him, avoided him, and doubted that he was a disciple.

After Barnabas brought him to the apostles, introduced him, vouched for him, and testified that he had seen the Lord and had preached boldly in Jesus' name at Damascus, the apostles and disciples accepted him. Being with them coming in and going out means he lived, moved, joined, and associated openly and freely among the believers in Jerusalem. Peter and James welcomed him, and the former persecutor who had once threatened them was now united with them, no longer feared and avoided but welcomed, loved, and respected.

He soon ministered actively and boldly in the synagogue, preaching Jesus as the Son of God, telling of his experience and conversion and the change in his life, and using prophecy as Stephen had done to show that Jesus who had been crucified is the Son of God. His presence and preaching strengthened the disciples and helped bring new converts to the faith. Their acceptance of him, together with his bold preaching, provided evidence that his Christian experience was genuine. God guarded him so that he could fulfill his mission and suffer for Jesus.

His testimony angered the priests and rulers, and the Jewish leaders sought to kill him. While praying he received Jesus' direction in vision to leave Jerusalem because its people would not accept his testimony, and though he thought his former persecution of believers and his part in Stephen's death might persuade them, Jesus sent him to preach to the Gentiles. The chapter to which the verse belongs shows Saul while unconverted hunting up souls to persecute under Satan's use, as a lesson that without the converting power of God coming to the soul the same will happen again, with unconverted men working with all their power as the satanic agencies did when they crucified Jesus Christ the only begotten Son of God, so that history is to be repeated. Great education and long experience give no help unless they perfect the knowledge of the glory of God to exalt the Lord Jehovah and His only begotten Son Jesus Christ, because Lucifer's act to exalt himself will give him power over just such men in present and future experience.