Charles Ellicott Commentary John 13:21

"When Jesus had thus said, he was troubled in the spirit, and testified, and said, Verily, verily, I say unto you, that one of you shall betray me." — John 13:21 (ASV)

He was troubled in spirit. Compare the note on John 11:33. He has spoken of the future of those who are true to their commission as Apostles. He now turns in deep emotion to him of whom those words cannot be spoken. The phrase Verily, verily, and the three verbs, was troubled, bore witness, spoke, perhaps imply that there was a pause in which His feeling checked His words, but that the witness to the truth demanded that they should be spoken, painful as they were. For the words themselves, compare the note on Matthew 26:21.