Mark 14:22

(ubi sup.) Even now also that Christ is close to us; He who prepared that table, Himself also consecrates it. For it is not man who makes the offerings to be the Body and Blood of Christ, but Christ who was crucified for us. The words are spoken by the mouth of the Priest, and are consecrated by the power and the grace of God. By this word which He spoke, This is my body, the offerings are consecrated; and as that word which says, Increase and multiply, and fill the earth, (Gen. 1:28) was sent forth but once, yet has its effect throughout all time, when nature does the work of generation; so also that voice was spoken once, yet gives confirmation to the sacrifice through all the tables of the Church even to this day, even to His advent.

(ubi sup.) Let there not be therefore a Judas at the table of the Lord; this sacrifice is spiritual food, for as bodily food, working on a belly filled with humours which are opposed to it, is hurtful, so this spiritual food if taken by one polluted with wickedness, rather brings him to perdition, not by its own nature, but through the fault of the recipient. Let therefore our mind be pure in all things, and our thought pure, for that sacrifice is pure. There follows: And he said unto them, This is my blood of the New Testament, which is shed for many.

(Mor. ii. 37) When His Passion was approaching, He is said to have taken bread and given thanks. He therefore gave thanks, who took upon Him the stripes of other men's wickedness; He who did nothing worthy of smiting, humbly gives a blessing in His Passion, to show us, what each should do when beaten for his own sins, since He Himself bore calmly the stripes due to the sin of others; furthermore to show us, what we who are the subjects of the Father should do under correction, when He who is His equal gave thanks under the lash.

(ubi sup.) When the rites of the old Passover were finished, He passed to the new, in order, that is, to substitute the Sacrament of His own Body and Blood, for the flesh and blood of the lamb. Wherefore there follows: And as they did eat, Jesus took bread; that is, in order to show that He Himself is that person to whom the Lord swore, Thou art a Priest for ever after the order of Melchizedec. (Ps. 110:4) There follows: And blessed, and brake it. (ubi sup.) He Himself also breaks the bread, which He gives to His disciples, to show that the breaking of His Body was to take place, not against His will, nor without His intervention; He also blessed it, because He with the Father and the Holy Spirit filled His human nature, which He took upon Him in order to suffer, with the grace of Divine power. He blessed bread and brake it, because He deigned to subject to death His manhood, which He had taken upon Him, in such a way as to show that there was within it the power of Divine immortality, and to teach them that therefore He would the more quickly raise it from the dead. There follows: And gave to them, and said, Take, eat: this is my body.

That is, giving thanks, He brake it, which we also do, with the addition of some prayers. That, namely, which I now give and which ye take. But the bread is not a mere figure of the Body of Christ, but is changed into the very Body of Christ. For the Lord said, The bread which I give you is my flesh. But the flesh of Christ is veiled from our eyes on account of our weakness, for bread and wine are things to which we are accustomed, if however we saw flesh and blood we could not bear to take them. For this reason the Lord bending Himself to our weakness keeps the forms of bread and wine, but changes the bread and wine into the reality of His Body and Blood. Some say that Judas did not partake in these mysteries, but that he went out before the Lord gave the Sacrament. Some again say that He gave him also of that Sacrament.