Barnabas was ready to go with Paul, but wished to take with them Mark, who had again decided to devote himself to the ministry. To this Paul objected. He "thought not good to take . . . with them" one who during their first missionary journey had left them in a time of need. He was not inclined to excuse Mark's weakness in deserting the work for the safety and comforts of home. He urged that one with so little stamina was unfitted for a work requiring patience, self-denial, bravery, devotion, faith, and a willingness to sacrifice, if need be, even life itself. So sharp was the contention that Paul and Barnabas separated, the latter following out his convictions and taking Mark with him. "So Barnabas took Mark, and sailed unto Cyprus; and Paul chose Silas, and departed, being recommended by the brethren unto the grace of God."

Barnabas var parat til at drage med Paulus, men ville også gerne, at de tog Markus med, da han atter havde besluttet at give sit liv til tjenesten for Gud. Men Paulus satte sig imod det. Han "holdt på, at de ikke skulle tage en med," som på deres første missionsrejse havde forladt dem i farens stund. Han var ikke tilbøjelig til at undskylde Markus svaghed, da han forlod arbejdet og valgte hjemmets tryghed og hygge. Han hævdede, at et menneske med så ringe modstandskraft ikke egnede sig til en gerning, der krævede tålmodighed, selvfornægtelse, mod, gudsfrygt, tro og offervillighed, om det så skulle gælde selve livet. Striden blev så hård, at Paulus og Barnabas skiltes, og den sidste fulgte sin overbevisning og tog Markus med sig. "Så tog Barnabas Markus med sig og afsejlede til Kypern. Men Paulus valgte sig Silas og drog ud, efter at brødrene havde givet ham Herrens nåde i vold."