To the laity are given Both Kinds in the Sacrament of the Lord's Supper, because this usage has the commandment of the Lord in Matt.26, 27: Drink ye all of it, where Christ has manifestly commanded concerning the cup that all should drink.
And lest any man should craftily say that this refers only to priests, Paul in 1 Cor.11,27 recites an example from which it appears that the whole congregation did use both kinds. And this usage has long remained in the Church, nor is it known when, or by whose authority, it was changed; although Cardinal Cusanus mentions the time when it was approved. Cyprian in some places testifies that the blood was given to the people. The same is testified by Jerome, who says: The priests administer the Eucharist, and distribute the blood of Christ to the people. Indeed, Pope Gelasius commands that the Sacrament be not divided (dist. II., De Consecratione, cap. Comperimus). Only custom, not so ancient, has it otherwise. But it is evident that any custom introduced against the commandments of God is not to be allowed, as the Canons witness (dist. III., cap. Veritate, and the following chapters). But this custom has been received, not only against the Scripture, but also against the old Canons and the example of the Church. Therefore, if any preferred to use both kinds of the Sacrament, they ought not to have been compelled with offense to their consciences to do otherwise. And because the division of the Sacrament does not agree with the ordinance of Christ, we are accustomed to omit the procession, which hitherto has been in use.