Acts 15:34-41 Strengthening The Churches.
When they had encouraged the church at Antioch through the news of the decision of the General Assembly, and strengthened them in the word, Barsabbas (Judas) and those who traveled with him decided to return to Jerusalem (v. 33). However, Barnabas, Paul, and Silas decided to stay, “teaching and preaching the word of the Lord, with many others also” (v. 35). Then Barnabas and Paul decided that they wanted to similarly strengthen other churches which they had been instrumental in planting. It must have occurred to them, through this recent experience with Antioch and the General Assembly at Jerusalem, that the other churches should also be visited, to see how they were doing (v. 36).
However, a dispute arose concerning John Mark, who had not gone on with them in Pamphilia (vv. 37-38 Cf. 13:13). So ultimately Barnabas would go with him to Barnabas’ hometown of Cyprus (Cf. 4:36), and Paul would take Silas and go to Syria and Cilicia. We should not totally dismiss these sharp contentions, because in this case it actually led to reaching more churches and people then they might otherwise have reached (vv. 39-41). This dispute also did not keep the church at Antioch from commending them to the grace of God for their respective work, even as they had been commended at the beginning (v. 40 Cf. 11:23; 14:26). Ultimately the goal was to strengthen the churches (v. 41 Cf. 16:5).