1 Corinthians 11:24,25
This is My Body which shall be delivered for you: this chalice is the new testament in My Blood, saith, the Lord: do this, as often as you receive it, in commemoration of Me.
Haydock
Verse 24. Juvenius, a native of Spain, and a priest, who flourished under Constantine the Great, about the year 329, has left us the life of Christ in hexameter verse, where speaking of the institution of the eucharist, he says, “Christ taught his disciples, that he delivered to them his own body;” and when he gave them the chalice, “he taught them that he had distributed to them his blood: and said, this blood remits the sins of the people: drink this, it is mine.” Bibl. Max. P. P. T. iv. p. 74.
Discipulos docuit proprium se tradere corpus, Edocuitque suum se divisisse cruorem. Atque ait: Hic sanguis populi delicta remittit: Hunc potate meum.
Denzinger
875—The Reason for the Institution of this Most Holy Sacrament
JULIUS III 1550-1555 COUNCIL OF TRENT SESSION XIII (Oct. II, 1551) Decree On the Most Holy Eucharist
Our Savior, therefore, when about to depart from this world to the Father, instituted this sacrament in which He poured forth, as it were, the riches of His divine love for men, “making a remembrance of his wonderful works” [Ps. 110:4], and He commanded us in the consuming of it to cherish His “memory” [1 Cor. 11:24], and “to show forth his death until He come” to judge the world [1 Cor. 11:23]. But He wished that this sacrament be received as the spiritual food of souls [Matt. 26:26], by which they may be nourished and strengthened [can. 5], living by the life of Him who said: “He who eateth me, the same also shall live by me” [John 6:58], and as an antidote, whereby we may be freed from daily faults and be preserved from mortal sins. He wished, furthermore, that this be a pledge of our future glory and of everlasting happiness, and thus be a symbol of that one “body” of which He Himself is the “head” [1 Cor. 11:23; Eph. 5:23], and to which He wished us to be united, as members, by the closest bond of faith, hope, and charity, that we might “all speak the same thing and there might be no schisms among us” [cf. 1 Cor. 1:10].