This verse functions as a parenthetical statement, and so Good News Translation has placed it in parentheses. In the Greek text Jesus is literally “he.” Who was going to betray him (so most translations) is rendered by New American Bible “his betrayer.” However this translation opens the possibility for a misunderstanding (note New American Bible “he knew his betrayer”). That is, to translate as a noun (“betrayer”), rather than as a phrase (who was going to betray him), may imply more acquaintance with the person, rather than knowledge about the person’s intentions.

As mentioned in other contexts, there is usually no difficulty in finding an appropriate term for betray, since this kind of behavior is universal. If no specific term is adequate to render betray, it is always possible to describe the action as “hand him over to enemies” or “cause him to be arrested by enemies.”

All of you, except one, are clean is rendered by Revised Standard Version “You are not all clean.” The same observation can be made about the statement here as was made in the discussion of verse 10.

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 .