John 13:21

Ταῦτα εἰπὼν … παραδώσει με. Two elements in the company had prevented Jesus from freely uttering His last counsels to the Twelve. (1) They had manifested dissension which would prevent them from acting together when He was gone, and a temper which would prevent them from receiving His words. And (2) there was among them a, traitor. The first element of discord had been removed by the feet-washing. He now proceeds to eliminate the second. But to have at once named the traitor would have been fatal. Peter and the rest would have taken steps to defeat, if not to put an end to Judas. Therefore He merely says, εἶς ἐξ ὑμῶν παραδώσει με. This it was which troubled His spirit, that one of the Twelve whom He had so cherished should turn traitor, using the familiarity and knowledge of intimacy to betray Him.