What happened on their tramp to that seaside city, we gather from the account in Mark’s Gospel, which says: “And they came into Capernaum. Now when he was inside the house he put the question to them: ‘What were you arguing over on the road?’

Mark 9:33, 34.

7. Why had their argument naturally involved Kingdom concerns?

⁷ Evidently, on the road, the apostles had trailed behind their Leader, Jesus. Yet, in some way, he discerned that an argument had arisen among them, with some heated expression of that fact. It was proper for him to see to it that an argument was settled among his followers. His approach to the matter indicates that he knew the subject of their discussion.