Presumably the Christian believers in Jerusalem think that Saul will be safe if he is in his home town. Sending Saul back to Tarsus not only spares his life in Jerusalem, but it will also give him a chance to testify to Christ amongst those living in Cilicia. We can assume that Saul was involved in missionary work in the regions of Cilicia and Syria after he left Jerusalem (Acts 15:23, Acts 15:41).1 He would stay in Tarsus for many years until he is invited by Barnabas to go and help in Antioch (Acts 11:25–26).2
30 And when the brothers learned this, they brought him down to Caesarea and sent him off to Tarsus.