John Lightfoot on John 13:33

[Little children.] "'Behold, I and the children whom the Lord hath given me,' Isaiah 8:18. Were they indeed his sons, or were they not rather his disciples? Hence you may learn that any one's disciple is called his son." Nor is it unlikely but that Christ in calling his disciples here My little children might have an eye to that place in Isaiah: for when the traitor, the son of perdition, had removed himself from them, he could then properly enough say, "Behold, I and the children which thou hast given me."