A.T. Robertson Commentary John 6:56

"He that eateth my flesh and drinketh my blood abideth in me, and I in him." — John 6:56 (ASV)

Abideth in me and I in him (εν εμο μενε καγω εν αυτω). Added to the phrase in 54 in the place of εχε ζωην αιωνιον (has eternal life). The verb μενω (to abide) expresses continual mystical fellowship between Christ and the believer as in 15:4-7; 1 John 2:6,27,28; 3:6,24; 4:12,16. There is, of course, no reference to the Lord's Supper (Eucharist), but simply to mystical fellowship with Christ.