Charles Spurgeon Commentary Acts 8:1

"And Saul was consenting unto his death. And there arose on that day a great persecution against the church which was in Jerusalem; and they were all scattered abroad throughout the regions of Judaea and Samaria, except the apostles." — Acts 8:1 (ASV)

Saul, having tasted blood in the murder of Stephen, became more and more furious in his persecution of the Church of Christ at Jerusalem, and the believers had to escape for their lives. They all did so, except the apostles, who were specially cared for by divine providence.