John 6:56

56.He who eateth my flesh. This is another confirmation; for while he alone has life in himself, he shows how we may enjoy it, that is, by eating his flesh; as if he had affirmed that there is no other way in which he can become ours, than by our faith being directed to his flesh. For no one will ever come to Christ as God, who despises him as man; and, therefore, if you wish to have any interest in Christ, you must take care, above all things, that you do not disdain his flesh.

Dwelleth in me, and I in him. When he says that he dwelleth in us, the meaning is the same as if he had said, that the only bond of union, and the way by which he becomes one with us, is, when our faith relies on his death. We may likewise infer from it, that he is not now speaking of the outward symbol, which many unbelievers receive equally with believers, and yet continue separated from Christ. It enables us also to refute the dream of those who say, that Judas received the body of Christ as well as the other apostles, when Christ gave the bread to all; for as it is a display of ignorance to limit this doctrine to the outward sign, so we ought to remember what I have formerly said, that the doctrine which is here taught is sealed in the Lord’s Supper. Now, it is certain, in the first place, that Judas never was a member of Christ; secondly, it is highly unreasonable to imagine the flesh of Christ to be dead and destitute of the Holy Spirit; and, lastly, it is a mockery to dream of any way of eating the flesh of Christ without faith, since faith alone is the mouth — so to speak — and the stomach of the soul.