Chapter 61 — On the Eucharist

Just as the life of the body needs material nourishment not only that the body may grow, but also for its natural upkeep, lest it wear away through continual dissolution and lose all its strength, so too was spiritual nourishment needed for the spiritual life, so that those who have been born again may both be sustained and grow in virtue.

And since spiritual effects are bestowed under visible symbols, as stated above, (Ch. 56.) it was fitting that this spiritual element should be given to us under the forms of those things which man uses most commonly for the nourishment of the body. Such are bread and wine. Therefore, this sacrament is conferred under the appearances of bread and wine.

We must take note, however, that in corporeal things there is a difference between the union of begetter with begotten, and that of nourishment with the subject nourished. The begetter and the begotten need not be united in substance, but only in likeness and power, but nourishment needs to be united to the body nourished in its very substance. Consequently, that the material symbols may correspond to their spiritual effects, in baptism (which is spiritual regeneration), the mystery of the incarnate Word is united to us in one way; and in another way in the sacrament of the Eucharist, which is spiritual nourishment. The Word incarnate is present in the sacrament of baptism by his power only, but we confess him to be present by his very substance in the sacrament of the Eucharist.

And because our salvation was consummated by Christ’s Passion and death, in which his blood was separated from his body, the sacrament of his body is delivered to us separately under the form of bread, and his blood under the form of wine. Thus this sacrament is a memorial and representation of our Lord’s Passion. In this way were our Lord’s words fulfilled: My flesh is food indeed, and my blood is drink indeed (John 6:55).