They had a sharp disagreement, so that they parted company. Barnabas took along Mark and sailed away to Cyprus,
[Acts 15:39 NET]
Only the generous interest of Barnabas in him gave John Mark his second chance. He had sadly failed in his first.
He started with Paul and Barnabas on their missionary tour, but returned home. He now wanted a chance to redeem himself, and Paul would not take him again. Barnabas was his friend, however, and thus Mark got a new start and became a worthy and useful man.
Barnabas seems to have been right, though this cost him the friendship of Paul. The two men quarrelled and separated. But Mark was worth saving from his failure.
Paul did not mean to go into Europe, but other doors which he sought to enter were shut against him, and a divine vision called him to the new continent. It was a beautiful beginning, there on the river bank, that Sabbath, when Paul found a little company of women at their worship, and told them about Christ, and when at least one woman opened her heart to Christ and her home to the missionaries.