But ye shall not be so - Christ here takes occasion to explain the nature of his kingdom. He assures them that it is established on different principles from those of the world; that his subjects were not to expect titles, and power, and offices of pomp in his kingdom. He that would be most advanced in “his” kingdom would be he that was most humble; and in order to show them this, he took a towel and girded himself after the manner of a servant, and washed their feet, to show them what ought to be their feelings toward each other. See John 13:4-17.
He that sitteth at meat - The master of the feast, or one of his guests.
But I am among you ... - This was said in connection with his washing their feet. He “showed” them how they ought to feel and act toward each other. “They” ought, therefore, not to aim at office and power, but to be humble, and serve and aid one another.