‘In that hour the disciples came to Jesus, saying, “Who then is greatest within the Kingly Rule of Heaven?” '
‘In that hour' is similar to ‘at that time' and connects what is now said with what has just gone before. Three of them (Peter, James and John) were probably already feeling a little smug, with ambitions that were growing (Matthew 20:20-21). They were no doubt conscious that they had been ‘picked out' and had experienced His glory in the mountain, although none of the others knew about that yet. How difficult it must have been for the three to keep their mouths shut when the argument was progressing. Yet perhaps it was their very silence about what had happened that had provoked the arguments about greatness. They were possibly seen as getting above themselves.
For none of the disciples seems to have had any doubt about their own coming importance or worthiness for it, and the fact that it was clearly something that they had all been arguing about on the way to where they were (Mark 9:33-34) demonstrates how important it was to them. It could even have been argued (by them) that it was ‘seeking the Kingly Rule of God and His righteousness', for their success would surely ensure the success of the Kingly Rule of God. But in their hearts they all knew perfectly well that Jesus would see them as being in the wrong, and that somehow this was not in accord with what Jesus had taught them. That is why they had hoped to keep it from Him. And thus at His questioning them as to what they had been talking about they were ashamed. However, in the end one of them obviously owned up to it and they then followed it up by asking, “Who then is greatest within the Kingly Rule of Heaven?”
The implication behind the question was not necessarily as to who was to be their leader, for they probably thought in terms of group leadership, but rather as to who would occupy the highest positions, and what the requirements would be. They wanted a rating and some assurance of their value. They did not want to lose out. (And James and John would shortly attempt to pre-empt them all (Matthew 20:20-21) so the lesson given here was not easily learned).
The question refers the readers back in their minds to Matthew 5:19 where what it is to be great within the Kingly Rule of Heaven is described. They should therefore have known the answer. It was to love God's Law and observe and teach it. But the last thing that had been in their minds when they were discussing together was of being humble teachers.
Thus this was a good question with which to open words about relationships and responsibilities under the Kingly Rule of Heaven, for it enabled Jesus to put the emphasis right back where it needed to be, on humility. (A further link back to chapter 5 is found in Matthew 18:8-9, see Matthew 5:29-30). So the sermon on the mount is to be seen as very much involved with this teaching about the beginnings of the new congregation.
(Two thousand years have passed by and even today Christian leaders have not changed. They still pride themselves on their status, and vie for importance, for the lesson is hard to learn. It is not too difficult to be superficially humble when we know that people regard us with awe. Then we can gently smile and let others tell us how wonderful we are. What is more difficult is being truly humble and genuinely having no regard for position at all. And that is a lesson that few have fully learned. If we still think of our position and grading, and of our own importance, then we have not yet become ‘great' within the Kingly Rule of Heaven. We are nonentities in God's eyes, whatever we think of ourselves, and whatever others think of us).
Notice that the question assumes the presence of the Kingly Rule of Heaven among them, otherwise none could be greatest in it, and that was the question that they had been discussing among themselves (Mark 9:34, compare also Matthew 18:4; Matthew 18:23-35). This can be seen as confirmed in two other places where greatness is connected with the Kingly Rule of Heaven. The first is in Matthew 5:18-20 where we were told that ‘those who do and teach His commandments will be called great in the Kingly Rule of Heaven', whereas those who are more lax about them will be called least in the Kingly Rule of Heaven, and those who are off the mark altogether cannot even enter within the Kingly Rule of Heaven. The second is in Matthew 11:11 where we learned that ‘he who is least in the Kingly Rule of Heaven is greater than John the Baptist', signifying that there was at the time a Kingly Rule of Heaven (otherwise the saying is meaningless, for John would unquestionably be in the future Kingly Rule of Heaven, and ‘great' within it). It gains its point from the fact that to be within the new Kingly Rule of Heaven now that Jesus was here was to be of higher status than the prophets of old. Thus present greatness of this kind was possible because the Kingly Rule of Heaven was here, it was coming in forcefully (Matthew 11:12), it was among them (Luke 17:21), they were sons of the Kingly Rule (Matthew 13:38).
But His disciples should have taken the hint from these verses as to what that greatness consists of. It is a greatness of quality. It consists of fully following His commandments, of partaking in the new age because they serve Him. The thought is of living to please God, of doing only the will of His Father in Heaven (Matthew 7:21; Matthew 12:50). But that was in fact the opposite of what the disciples were now seeking. Their thoughts now were not on doing the will of the Father but on how to make sure that they obtained the best places for themselves. So their failure here is not just to be seen as resulting from ignorance, but as resulting from an unwillingness to recognise and face up to the truth, and to have the right attitude towards it. The truth was that they were still sinners, and often still looking in the wrong direction.
For in this case they were failing to ‘seek the Kingly Rule of God and His righteousness' (Matthew 6:33) and were seeking self-aggrandisement. They had forgotten the lessons so hardly learned and memorised (as we also so easily do). Practicalities had taken over (after all we must be practical). They were soon, however, to learn to their shame that they were looking in the wrong direction. True greatness, they were to find, would be discovered by taking the opposite path to the way that they had in mind. It would be found by eschewing greatness and seeking the way of service and humility (Matthew 20:26-28).