Paul, Barnabas, and John Mark left Cyprus and sailed to the southern coast of Turkey—a land then known as Pamphylia, whose rugged coastline ascended sharply into the towering heights of a mountain range steeper and fiercer than the eastern Tauras near Tarsus, and more terrible than any hills known to the Cypriot Barnabas or the Judean John Mark.
That sight alone may have initiated the storm surge of doubt that would eventually flood young John Mark's soul. In this region Paul became gravely ill with malaria or some other serious coastal fever. That may have been the last straw for the inexperienced traveler to endure. Without any explanation, Luke simply writes, "John left them and returned to Jerusalem." But going on from Perga, they pressed on. Without even as much as a hiccup, the journey continued. Paul and Barnabas were undeterred by John Mark's desertion.
Here's an important observation: all the way through ministry, people leave. In every church there will be individuals who, for whatever reason, move on to other things. This includes those in leadership. They leave, but the church presses on. Regardless of the circumstances surrounding their departure, the journey continued. For Paul and Barnabas there was neither time nor need for a long, drawn-out farewell. They pressed ahead, keeping their eyes focused on the goal.
It's hard to press on when you feel abandoned. It's easy to give in to discouragement and allow that to siphon your tank dry, but Paul and Barnabas had no such luxury. Emotions in check, they had a job to do. So they moved forward with an even stronger determination.
One of the marks of maturity is the ability to press ahead regardless of who walks off the scene. The alternative isn't an option. Once you've said goodbye, it's time for everyone to move on. That's exactly what Paul and Barnabas did. As Paul wrote in his letter to the Philippians: "I press on toward the goal for the prize of the upward call of God in Christ Jesus" (3:14).