John 13:18

This blessedness, He knew, could not attach to all of them: οὐ περὶ πάντων ὑμῶν ὑμῶν λέγω, “I speak not of you all,” I do not expect all of you to fulfil the condition of blessedness, ἐγὼ οἶδα οὓς ἐξελεξάμην, “I for my part (in contrast to the disciples who were in ignorance) know the men whom I have chosen as Apostles,” and am therefore not taken by surprise by the treachery of one of them. For the choice of Judas see John 6:70, where the same word ἐξελεξάμην is used. ἀλλʼ ἵνα … The simplest construction is: “but I chose Judas in order that,” etc. This may not, however, involve that Jesus consciously chose Judas for this purpose. That is not said, and can scarcely be conceived. The Scripture which waited for fulfilment is Psalms 40:9, ὁ ἐσθίων ἄρτους μου ἐμεγάλυνεν ἐπʼ ἐμὲ πτερνισμόν. Eating bread together is in all countries a sign, and in some a covenant or pledge of friendship. Cf. Kypke on ὁμοτράπεζος and Trumbull's Blood Covenant, p. 313, and Oriental Life, p. 361. Here the fact of Judas' eating bread with Jesus is introduced as aggravating his crime. “To lift the heel” is to kick, whether originally used of a horse or not; and expresses violence and contempt.