It only remains that the whole become ours by application. This is done by means of the gospel, and more clearly by the sacred Supper, where Christ offers himself to us with all his blessings, and we receive him in faith. The sacrament, therefore, does not make Christ become for the first time the bread of life; but, while it calls to remembrance that Christ was made the bread of life that we may constantly eat him, it gives us a taste and relish for that bread, and makes us feel its efficacy. For it assures us, first, that whatever Christ did or suffered was done to give us life; and, secondly, that this quickening is eternal; by it we are ceaselessly nourished, sustained, and preserved in life. For as Christ would not have not been the bread of life to us if he had not been born, if he had not died and risen again; so he could not now be the bread of life, were not the efficacy and fruit of his nativity, death, and resurrection, eternal. All this Christ has elegantly expressed in these words, “The bread that I will give is my flesh, which I will give for the life of the world” (John 6:51); doubtless intimating, that his body will be as bread in regard to the spiritual life of the soul, because it was to be delivered to death for our salvation, and that he extends it to us for food when he makes us partakers of it by faith. Wherefore he once gave himself that he might become bread, when he gave himself to be crucified for the redemption of the world; and he gives himself daily, when in the word of the gospel he offers himself to be partaken by us, inasmuch as he was crucified, when he seals that offer by the sacred mystery of the Supper, and when he accomplishes inwardly what he externally designates. Moreover, two faults are here to be avoided. We must neither, by setting too little value on the signs, dissever them from their meanings to which they are in some degree annexed, nor by immoderately extolling them, seem somewhat to obscure the mysteries themselves. That Christ is the bread of life by which believers are nourished unto eternal life, no man is so utterly devoid of religion as not to acknowledge. But all are not agreed as to the mode of partaking of him. For there are some who define the eating of the flesh of Christ, and the drinking of his blood, to be, in one word, nothing more than believing in Christ himself. But Christ seems to me to have intended to teach something more express and more sublime in that noble discourse, in which he recommends the eating of his flesh—viz. that we are quickened by the true partaking of him, which he designated by the terms eating and drinking, lest any one should suppose that the life which we obtain from him is obtained by simple knowledge. For as it is not the sight but the eating of bread that gives nourishment to the body, so the soul must partake of Christ truly and thoroughly, that by his energy it may grow up into spiritual life. Meanwhile, we admit that this is nothing else than the eating of faith, and that no other eating can be imagined. But there is this difference between their mode of speaking and mine. According to them, to eat is merely to believe; while I maintain that the flesh of Christ is eaten by believing, because it is made ours by faith, and that that eating is the effect and fruit of faith; or, if you will have it more clearly, according to them, eating is faith, whereas it rather seems to me to be a consequence of faith. The difference is little in words, but not little in reality. For, although the apostle teaches that Christ dwells in our hearts by faith (Eph. 3:17), no one will interpret that dwelling to be faith. All see that it explains the admirable effect of faith, because to it it is owing that believers have Christ dwelling in them. In this way, the Lord was pleased, by calling himself the bread of life, not only to teach that our salvation is treasured up in the faith of his death and resurrection, but also, by virtue of true communication with him, his life passes into us and becomes ours, just as bread when taken for food gives vigour to the body.

—John Calvin, Institutes of the Christian Religion, (IV, xvii, 5), translated by Ford Lewis Battles.