But many that are first shall be last; and the last first. Most fitly does our Lord add this weighty sentence to what has just gone before. For thus he places himself, his grace, and his gospel in direct opposition to the corrupt teaching of the scribes and Pharisees.
Perhaps the disciples thought within themselves, "How can it come to pass that we, the poor, the unlearned, the despised, are to sit upon thrones judging the twelve tribes of Israel, amongst whom are men far our superiors in station, in learning, and in authority, such as are the scribes and Pharisees, and that rich young ruler just mentioned."
Our Lord here teaches them that the future will reveal great changes—that some who are first here will be last there, and some who seem last here will be first there. The disciples, and others like them, who, having forsaken all and followed Christ, seemed to be last in this world, will be first in the world to come—most dear to Christ, the King of Heaven, in their lives; most like to him in their zeal for his cause.