Acts 4:29

But Barnabas took him and brought him to the apostles and recounted to them how he had seen the Lord on the road, and that He had talked to him, and how at Damascus he had spoken out boldly in the name of Jesus.

So he was with them, moving about freely in Jerusalem, speaking out boldly in the name of the Lord.

Therefore they spent a long time there speaking boldly with reliance upon the Lord, who was testifying to the word of His grace, granting that signs and wonders be done through their hands.

Therefore having such a hope, we use great boldness,