Acts 15:37 in the World English Bible
Barnabas planned to take John, who was called Mark, with them also.
Context
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.