John 6:56

"He that eateth My flesh, dwelleth in Me." This He said, showing that such an one is blended with Him. Now what follows seems unconnected, unless we enquire into the sense; for, saith some one, after saying, "He that eateth My flesh, dwelleth in Me," what kind of a consequence is it to add, "As the living Father hath sent Me, and I live by the Father"? Yet the words harmonize perfectly. For since He continually spake of "eternal life," to prove this point He introduceth the expression, "dwelleth in Me"; for "if he dwelleth in Me, and I live, it is plain that he will live also." Then He saith, "As the living Father hath sent Me." This is an expression of comparison and resemblance, and its meaning is of this kind, "I live in like manner as the Father liveth." And that thou mayest not deem Him unbegotten, He immediately subjoineth, "by the Father," not by this to show that He needeth, in order to live, any power working in Him, for He said before, to remove such a suspicion, "As the Father hath life in Himself, so hath He given to the Son also to have life in Himself"; now if He needeth the working of another, it will be found that either the Father hath not given Him so to have it, and so the assertion is false, or if He hath so given it, then He will need no other one to support Him. What then means the, "By the Father"? He here merely hinteth at the cause, and what He saith is of this kind: "As the Father liveth, so I live, and he that eateth Me shall live by Me." And the "life" of which He speaketh is not life merely, but the excellent life; for that He spake not simply of life, but of that glorious and ineffable life, is clear from this. For all men "live," even unbelievers, and uninitiated, who eat not of that flesh. Seest thou that the words relate not to this life, but to that other? And what He saith is of this kind: "He that eateth My flesh, when he dieth shall not perish nor suffer punishment"; He spake not of the general resurrection, (for all alike rise again,) but concerning the special, the glorious Resurrection, that which hath a reward.

(Hom. xlvii. 1) Or, having given a promise of eternal life to those that eat Him, He says this to confirm it: He that eateth My flesh, and drinketh My blood, dwelleth in Me, and I in him.

In a word, He now explains how that which He speaks of comes to pass, and what it is to eat His body and to drink His blood. "He that eateth my flesh, and drinketh my blood, dwelleth in me, and I in him." This it is, therefore, for a man to eat that meat and to drink that drink, to dwell in Christ, and to have Christ dwelling in him. Consequently, he that dwelleth not in Christ, and in whom Christ dwelleth not, doubtless neither eateth His flesh [spiritually] nor drinketh His blood [although he may press the sacrament of the body and blood of Christ carnally and visibly with his teeth], but rather doth he eat and drink the sacrament of so great a thing to his own judgment, because he, being unclean, has presumed to come to the sacraments of Christ, which no man taketh worthily except he that is pure: of such it is said, "Blessed are the pure in heart, for they shall see God."

Then He explains what it is to eat His body and drink His blood: He that eateth My flesh, and drinketh My blood, dwelleth in Me, and I in him. So then to partake of that meat and that drink, is to dwell in Christ and Christ in thee. He that dwelleth not in Christ, and in whom Christ dwelleth not, neither eateth His flesh, nor drinketh His blood: but rather eateth and drinketh the sacrament of it to his own damnation. (de Verb. Dom.) As for those, as indeed there are many, who either eat that flesh and drink that blood hypocritically, or, who having eaten, become apostates, do they dwell in Christ, and Christ in them? Nay, but there is a certain mode of eating that flesh, and drinking that blood, in the which he that eateth and drinketh, dwelleth in Christ, and Christ in him. (de Civ. Dei, l. xxi. c. 25) That is to say, such an one eateth the body and drinketh the blood of Christ not in the sacramental sense, but in reality.

For we do not eat God simply, God being impalpable and incorporeal; nor again, the flesh of man simply, which would not profit us. But God having taken flesh into union with Himself, that flesh is quickening. Not that it has changed its own for the Divine nature; but, just as heated iron remains iron, with the action of the heat in it; so our Lord's flesh is quickening, as being the flesh of the Word of God.