The increasingly urgent issue for Jesus must have been the behaviour and attitude of the disciples. He had taught them so much, modelled a way of living to them which should have been the goal for them, demonstrated what came from walking that holy path, confided the big picture to them and yet it was continuing to be a dim picture to them: their aims and commitments were so far removed from His that it must have seemed an unbridgable chasm to Him. These were to be His representatives on earth and without their complete commitment, the message of the coming of the Kingdom of God would not be heard. He could envisage them retreating to their old familiar jobs and ways of life at the first sense that the challenge ahead was going to be huge for them. Yes, they had given up three years of their lives to follow Him, it wasn't that they lacked commitment, but they just didn't understand! Here the group are again on the road, moving, always moving and as they walk, they are arguing about who was the greatest of them, who would get prime place at the Heavenly Feast. In one sense, it is encouraging to read that they saw this as a future reality, but they really hadn't comprehended what it would take to be in that place. Jesus had spoken to them about the pathway of suffering which lay ahead of Him and as His disciples they were called to emulate their Master in every way possible. The Messiahship of Jesus was primarily one of servanthood and yet somehow the disciples had missed that principle, their minds were infected by the long proclaimed banner that the Messiah would be the all-conquering King.
However, it is a salient point that when He asked them what they were discussing, they tried not to answer, they were ashamed of their conversation. When their argument had to be stated in the presence of Jesus it was seen in all its unworthiness. What things of ours would we be too embarrassed to bring before Jesus?
So, in the middle of their walk, with presumably a goal for the night in mind, Jesus sat down and called the disciples to Him. In effect, by sitting down He made it clear to His followers that He was now speaking as a Rabbi to His disciples, that this was something serious that they should listen seriously to. He told them that only by being servants of all could they find greatness in the Kingdom of Heaven. It is not that Jesus abolished ambition in these words, but He recreated and sublimated ambition: the ambition now would be to serve and to do things for others. The way of Jesus is not the way of the world: it is radically and consciously opposing that way, it is living a different way and if everyone chose to live this way, the world would be utterly transformed!