Not So Much His As Ours
Godly souls can gather great assurance and delight from this Sacrament; in it they have a witness of our growth into one body with Christ such that whatever is his may be called ours. As a consequence, we may dare assure ourselves that eternal life, of which he is the heir, is ours; and that the Kingdom of Heaven into which he has already entered, can no more be cut off from us than from him; again, that we cannot be condemned for our sins, from whose guilt he has absolved us, since he willed to take them upon himself as if they were his own. This is the wonderful exchange which, out of his measureless benevolence, he has made with us; that, becoming Son of man with us, he has made us sons of God with him; that, by his descent to earth, he has prepared an ascent to heaven for us; that, by taking on our mortality, he has conferred his immortality upon us; that, accepting our weakness, he has strengthened us by his power; that, receiving our poverty unto himself; he has transferred his wealth to us; that, taking the weight of our iniquity upon himself (which oppressed us), he has clothed us with his righteousness.
In this Sacrament we have such full witness of all these thikngs that we must certainly consider them as if Christ here present were himself set before our eyes and touched by our hands. For his word cannot lie or deceive us: ‘Take, eat, drink: this is my body, which is given for you; this is my blood, which is shed for forgiveness of sins.’ By bidding us take, he indicates that it is ours; by bidding us eat, that it is made one substance with us; by declaring that his body is given for us and his blood shed for us, he teaches that both are not so much his as ours. For he took up and laid down both, not for his own advantage but for our salvation.”
[John Calvin, “Union with Christ as the special fruit of the Lord’s Supper,” Institutes of the Christian Religion, IV.17.2–3]