John 13:26
“He it is, to whom I shall give a sop when I have dipped it.”
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.
Source: Homilies on the Gospel of John (New Advent)