“And Barnabas and Saul returned from Jerusalem, when they had fulfilled their ministry, and took with them John, whose surname was Mark.”
King James Version (KJV)
12:25 Saul returned - To Antioch; taking John, surnamed Mark - The son of Mary, (at whose house the disciples met, to pray for Peter,) who was sister to Barnabas.
Ac 12:25 Barnabas and Saul returned from Jerusalem. This verse is introductory to the next chapter, which introduces the era of Gentile missions. Ac 11:29,30 explains why they had gone to Jerusalem. See note. Took with them John, whose surname was Mark. He was a relative of Barnabas (Col 4:10). In the next chapter he appears as an associate in their missionary labors (Ac 13:5).