John Lightfoot on John 13:2

[And supper being ended.] I acknowledge the aorist, and yet do not believe the supper was now ended. We have the very same word in the story of the same supper, Matthew 26:6; and Jesus being in Bethany: which in St. Mark is and being in Bethany, chapter 14:3: so that supper being ended is no more than 'being' supper.

Let us join the full story together. While Jesus was at supper in the house of Simon the leper two days before the Passover, a woman comes and pours very precious ointment upon his head. When some murmured at the profuseness of the expense, he defends the woman and the action by an apology: and having finished his apology, he rises immediately from the table, as it were, in the very midst of supper, and girds himself to wash his disciples' feet: so that while they are grumbling at the anointing of his head, he does not disdain to wash their feet.

The reason of this extraordinary action of his we may in some measure spell out from those little prefaces the evangelist uses before he tells the story.

I. "When Jesus knew that his hour was come that he should depart out of this world, &c." [There is an expression not unlike this in Bemidbar Rabba; "Abraham said, 'I am flesh and blood, tomorrow I shall go out of this world.'"]

It had a little rubbed up the memory of his departure out of this world, that the woman had as it were anointed him for his funeral: and therefore he riseth immediately from the table, that he might give them some farewell token of his humility and charity, and leave them an example for the practice of these virtues one amongst another.

II. "The devil having now put into the heart of Judas to betray him," it was but seasonable for him to shew his disciples that he would strengthen and vindicate them against the wolf who had now stolen, I will not say a sheep, but a goat, and that out of his own flock. It must not pass unobserved, that 'his disciples' murmured at the lavish use of the ointment, Matthew 26:8; as if the murmuring humour was crept in amongst others also as well as Judas; which perhaps moved Christ the more earnestly to meet the beginnings of that distemper by this action.

III. "Knowing that the Father had given all things into his hands," verse 3, he gave the traitor over to Satan, and confirms the rest to himself: signifying, by the external washing, that his should be secured from the devil by the washing of Christ. Whosoever shall attempt the determination, whether he washed the feet of Judas or not, let him see how he will free himself of this dilemma:

If he washed Judas' feet, why had not he his part in Christ, as well as the rest of his disciples? For supposing that true, "If I wash thee not, thou hast no part with me," why should not this be so too, "If I do wash thee, thou hast a part with me?"

If he did not wash Judas with the rest, but left him out, how could the rest be ignorant who was the unclean person? verse 10, which they were altogether ignorant of.