Chapter 18 — Part II: The Sacraments — The Holy Eucharist
Section 182. The priest is also one and the same, Christ the Lord; for the ministers who offer Sacrifice, consecrate the holy mysteries, not in their own person, but in that of Christ, as the words of consecration itself show, for the priest does not say: This is the body of Christ, but, This is my body; and thus, acting in the Person of Christ the Lord, he changes the substance of the bread and wine into the true substance of His body and blood.