A.T. Robertson Commentary John 13:18

"I speak not of you all: I know whom I have chosen: but that the scripture may be fulfilled: He that eateth my bread lifted up his heel against me." — John 13:18 (ASV)

Not of you all (ου περ παντων). As in verse 11, he here refers to Judas whose treachery is no surprise to Jesus (6:64,70).

Whom I have chosen (τινας εξελεξαμην). Indirect question, unless τινας is here used as a relative like ους. The first aorist middle indicative of εκλεγω is the same form used in 6:70. Jesus refers to the choice (Luke 6:13 εκλεξαμενος, this very word again) of the twelve from among the large group of disciples. Θατ θε σχριπτυρε μιγτ βε φυλφιλλεδ (αλλ' ινα η γραφη πληρωθη). See the same clause in 17:12. Purpose clause with ινα and first aorist passive subjunctive of πληροω. This treachery of Judas was according to the eternal counsels of God (12:4), but none the less Judas is responsible for his guilt. For a like elliptical clause see 9:3; 15:25. The quotation is from the Hebrew of Ps 41:9.

He that eateth (ο τρωγων). Present active participle of old verb to gnaw, to chew, to eat, in N.T. only in John (6:54,56,57,58; 13:18) and Mt 26:38. LXX has here ο εσθιων.

Lifted up his heel against me (επηρεν επ' εμε την πτερναν αυτου). First aorist active indicative of επαιρω. Πτερνα, old word for heel, only here in N.T. The metaphor is that of kicking with the heel or tripping with the heel like a wrestler. It was a gross breach of hospitality to eat bread with any one and then turn against him so. The Arabs hold to it yet.