Catechism of the Catholic Church

610 Jesus gave the supreme expression of his free offering of himself at the meal shared with the twelve Apostles "on the night he was betrayed". ⁴²⁹ On the eve of his Passion, while still free, Jesus transformed this Last Supper with the apostles into the memorial of his voluntary offering to the Father for the salvation of men: "This is my body which is given for you." "This is my blood of the covenant, which is poured out for many for the forgiveness of sins." ⁴³⁰

611 The Eucharist that Christ institutes at that moment will be the memorial of his sacrifice. ⁴³¹ Jesus includes the apostles in his own offering and bids them perpetuate it. ⁴³² By doing so, the Lord institutes his apostles as priests of the New Covenant: "For their sakes I sanctify myself, so that they also may be sanctified in truth." ⁴³³