Chapter 18 — Part II: The Sacraments — The Holy Eucharist
Section 9. It is called, moreover, communion, the term being evidently borrowed from that passage of the Apostle where we read: The chalice of benediction which we bless, is it not the communion of the blood of Christ? And the bread which we break, is it not the partaking of the body of the Lord? For, as Damascene has explained, this Sacrament unites us to Christ, renders us partakers of His flesh and Divinity, reconciles and unites us to one another in the same Christ, and forms us, as it were, into one body.