Jesus answered,
He it is, to whom I shall give a morsel, when I have dipped it.
And when he had dipped the morsel, he gave it to Judas Iscariot, the son of Simon.
Read Chapter 13
Augustine of Hippo
AD 430
1. This short section of the Gospel, brethren, we have in this lesson brought forward for exposition, as thinking that we ought also to say something of the Lord's betrayer, as now plainly enough disclosed by the dipping and holding out to him of the piece of bread. Of that indeed which precedes, (namely), that Jesus, when about to point him out, was troubled in spirit, we have treated in our last discourse; but what I perhaps omitted to mention there, the Lord, by His own perturbation of spirit, thought proper to indicate this also, that it is necessary to bear with false brethren, and those tares that are among the wheat in the Lord's field until harvest-time, because that when we are compelled by urgent reasons to separate some of them even before the harvest, it cannot be done without disturbance to the Church. Such disturbance to His saints in the future, through schismatics and heretics, the Lord in a way foretold and prefigured in Himself, when, at the moment of that wicked man ...
We might naturally be filled with admiration, and especially from this further instance, at the zealous ardour displayed by the holy disciples in their love to God, and at the excessive strictness of their devotion. For being unable of themselves to know the guilty person, whoever he might be, and refusing also to place confidence in the uncertainties of deceitful conjectures, they again give vent to their curiosity by questions, and make one who was preeminent among them, I mean Peter, the representative of their eagerness to learn the truth. Peter shrinks from putting the question by his own mouth, and entrusts the interrogation to him who is reclining next to Christ and who is beloved for his more conspicuous purity, I mean John, the author of the book before us; who, in speaking of himself as beloved by Christ, has concealed his own name, burying it in silence, lest he might seem to any to be making a boastful display. For the mind of the saints is untainted by any such ambition. A...
Even the manner (of the rebuke) was calculated to put him to shame. He respected not the table, though he shared the bread; be it so; but the receiving the sop from His own hand, whom would not that have won over? Yet him it won not.