A.T. Robertson Commentary John 6:57

"As the living Father sent me, and I live because of the Father; so he that eateth me, he also shall live because of me." — John 6:57 (ASV)

The living Father (ο ζων πατηρ). Nowhere else in the N.T., but see 5:26 and "the living God" (Matthew 16:16; 2 Corinthians 6:16). The Father is the source of life and so "I live because of the Father" (καγω ζω δια τον πατερα).

He that eateth me (ο τρωγων με). Still bolder putting of the mystical appropriation of Christ (51,53,54,56).

Because of me (δι' εμε). The same idea appears in 14:19: "Because I live ye shall live also." See 11:25. Jesus Christ is our ground of hope and guarantee of immortality. Life is in Christ. There is no real difficulty in this use of δια with the accusative as with δια τον πατερα just before. It occurs also in 15:3. As the Father is the fount of life to Christ, so Christ is the fount of life to us. See 1 John 4:9 where δια is used with the genitive (δι' αυτου) as the intermediate agent, not the ground or reason as here.