Acts 15:35-39

But Paul and Barnabas stayed in Antioch, teaching and preaching the word of the Lord, with many others also. Second Missionary Journey

After some days Paul said to Barnabas, “Let’s return and visit the brothers and sisters in every city in which we proclaimed the word of the Lord, and see how they are.”

Barnabas wanted to take John, called Mark, along with them also.

But Paul was of the opinion that they should not take along with them this man who had deserted them in Pamphylia and had not gone with them to the work.

Now it turned into such a sharp disagreement that they separated from one another, and Barnabas took Mark with him and sailed away to Cyprus.