Acts 13:2-5 King James Version (KJV)
2 As they ministered to the Lord, and fasted, the Holy Ghost said, Separate me Barnabas and Saul for the work whereunto I have called them.
3 And when they had fasted and prayed, and laid their hands on them, they sent them away.
4 So they, being sent forth by the Holy Ghost, departed unto Seleucia; and from thence they sailed to Cyprus.
5 And when they were at Salamis, they preached the word of God in the synagogues of the Jews: and they had also John to their minister.
Acts 15:36-40 King James Version (KJV)
36 And some days after Paul said unto Barnabas, Let us go again and visit our brethren in every city where we have preached the word of the Lord, and see how they do.
37 And Barnabas determined to take with them John, whose surname was Mark.
38 But Paul thought not good to take him with them, who departed from them from Pamphylia, and went not with them to the work.
39 And the contention was so sharp between them, that they departed asunder one from the other: and so Barnabas took Mark, and sailed unto Cyprus;
40 And Paul chose Silas, and departed, being recommended by the brethren unto the grace of God.