“Likewise also the cup after supper, saying, This cup is the new testament in my blood, which is shed for you.”
Luke 22:20 — Greek Interlinear
Church Fathers on Luke 22:20
Having finished the rites of the old Passover, He passes on to the new, which He desires the Church to celebrate in memory of His redemption, substituting for the flesh and blood of the lamb, the Sacrament of His own Flesh and Blood in the figure of the bread and wine, being made a Priest for ever after the order of Melchisedech. Hence it is said, And he look bread, and gave thanks, as also He had given thanks upon finishing the old feast, leaving us an example to glorify God…
For the bread before the consecration is common bread, but when the mystery has consecrated it, it is, and it is called, the Body of Christ.
Nor doubt that this is true; for He plainly says, This is my body; but rather receive the words of your Savior in faith. For since He is the Truth, He lies not. They rave foolishly then who say that the mystical blessing loses its power of sanctifying, if any remains are left till the following day. For the most holy Body of Christ will not be changed, but the power of blessing and the life giving grace is ever abiding in it. For the life-giving power of God the Father is the…