Chrysostom notes how, even after all Jesus had said, the Apostles understood so little. Yes, as is the case so often with us, they were afraid to ask, so they received no answers.
They had not yet perceived that the key aspect of discipleship was servantship, and they still thought carnally and not with the Spirit. Discipleship starts, like a tree, with roots that go downwards before shoots can go upwards; humility is the root of servantship. As Gregory of Nyssa reminds us, Christians are not to be vainglorious, they are to live together in harmony, and we are not to seek self-promotion or position. This, the disciiples had not yet realised. As Christ reminds us here, the pattern for us is that of the child, whose hearts do not invent evil, and who hardly know what corruption is. If we are like unto this, then we shall dwell in the kingdom with God.
As so often with Mark, the Patristic commentators tell us little, preferring instead to concentrate on the other two synoptics and on John, but there is much in what Chrysostom, St Augustine and St Gregory say here.
We, like the disciples, long for the rewards of this world, if not glory and greatness, then wealth and power, or, at least some of the good things of this life. The Psalms speak about the glory God has destined for us. You have made them a little lower than God, and crowned them with glory and honor (Psalm 8:5). But Jesus, as usual, subverts our ideas. He embraces a child to show his disciples who really is the greatest in the kingdom of God. As in his dealings with women, Jesus turns to those without power or ‘agency’ in that society. Children were even lower on the rung than women. But Jesus elevates a little child in the presence of his disciples – making him, symbolically, the guest of honour at the right hand of God. The answer to the question od who is greatest in God’s kingdom is not the one we and the disciples thought. It is the one who is humble and lowly of heart. He emptied himself for us, he hung there so we should not. That, I think, helps make us humble. C451.