I am not talking about all of you (see verses 10-11) is an obvious reference to Judas.

I know those I have chosen may be taken in one of two ways: (1) It may mean “I know those men whom I have really chosen, but I have not chosen Judas”; (2) or it may mean “I know the kind of men I chose” (New American Bible). The second interpretation implies that Jesus did choose Judas, though he knew all along what his character was, even as he knew the character of the other men he chose. On the basis of passages such as 6.64,70, the second alternative seems to be the meaning here. That is, even the choice of the one who would betray Jesus was within the divine purpose; Jesus did not choose him without knowing his character.

In rendering I know those I have chosen, the term for know should be chosen carefully. It should not be an expression which merely means “be acquainted with.” The rendering of this clause should suggest “I know the kind of men I have chosen” or “I realize what sort of persons I have chosen.”

Come true translates the same verb used in 12.38 (most translations “be fulfilled”). Must come true may be rendered in some languages “must surely happen,” for example, “But what is written in the scriptures, ‘The man who ate with me turned against me,’ must surely happen.”

In the scripture quotation, which comes from Psalm 41.9, there is a textual problem. The text may read who ate my food (Good News Translation, Moffatt, Goodspeed, Phillips, Revised Standard Version, Zürcher Bibel, Luther); or it may read “who ate food with me” (New American Bible, New English Bible, Jerusalem Bible, La Sainte Bible: Nouvelle version Segond révisée). Because of the complexity of the problem, the UBS Committee on the Greek text rates the reading retained in the text a “D” choice, indicating a high degree of doubt. The manuscript evidence for “with me” is much stronger than for “my,” which is also the reading of the Septuagint. But the UBS Committee prefers the latter reading, because “with me” may be an assimilation to Mark 14.18. It is difficult to explain the basis for Die Bibel im heutigen Deutsch, which seems to follow a composite reading: “with whom I have shared my bread.” Whereas the specific term “bread” occurs in the Greek text, Good News Translation substitutes the more generic term food.

Turned against me (so also New English Bible, Die Bibel im heutigen Deutsch) is literally “has lifted his heel against me” (Revised Standard Version). Jerusalem Bible translates “rebels against me.” In the Near East to show the bottom of one’s foot to someone was a mark of contempt, or even possibly a threat of violence. It was an especially treacherous thing to do after eating at someone’s table, because eating a meal with a superior was a pledge of loyalty to that person (note 2 Sam 9.7, 13; 1 Kgs 18.19; 2 Kgs 25.29). Turned against me may be rendered in some languages “became my enemy” or “began to fight against me.”

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .