In John 13:18, Jesus says: "I am not referring to all of you; I know those I have chosen. But this is to fulfill this passage of Scripture: 'He who shared my bread has turned against me.'". The only passage of Scripture, that we currently know of, containing a statement similar to that is Psalm 41:9, which says: "Even my close friend whom I trusted, the one who shared my bread, has lifted up his heel against me."
If this isn't the passage that Jesus was referring to, if there is some Scripture that has been lost or that we are not aware of, then this question should be reconsidered.
However, if the passage that Jesus refers to is indeed Psalm 41:9, please explain to me why or how the Psalm could possibly refer to Him, considering that in verse 4 of the same Psalm, the psalmist says: "I said, 'Have mercy on me, Lord; heal me, for I have sinned against you'". Jesus was sinless, so why would we assume that verse 9 is a prophecy about Jesus while verse 4, which seems to be referring to the same person, is not a prophecy about Jesus?