The Conquest and Challenge YouCat number for July is all about one of the most generous acts Christ did while on earth.
#99 What happened at the Last Supper? Jesus washed the feet of his apostles on the evening before his death; he instituted the Eucharist and founded the priesthood of the New Covenant.
Catechism of the Catholic Church # 610 says: 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” (Roman Missal, EP III; cf. Mt 26:20; 1 Cor 11:23). 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” (Lk 22:19; Mt 26:28; cf. 1 Cor 5:7).