Bread and wine are offered, being the figure of the flesh and blood of Jesus Christ. They who participate in this visible bread eat, spiritually, the flesh of the Lord. (Macarius, Homily xxvii.)
For He, we know, who spoke of his natural body as corn and bread, and, again, called Himself a vine, dignified the visible symbols by the appellation of the body and blood, not because He had changed their nature, but because to their nature He had added grace. (Theodoret, Diologue I, Eranistes and Orthodoxus.)
For even after the consecration the mystic symbols are not deprived of their own nature; they remain in their former substance figure and form; they are visible and tangible as they were before. (Theodoret, Dialogue II, Eranistes and Orthodoxus.
For the Lord did not hesitate to say: “This is My Body”, when He wanted to give a sign of His body. (Augustine, Against Adimant.)
If the sentence is one of command, either forbidding a crime or vice, or enjoining an act of prudence or benevolence, it is not figurative. If, however, it seems to enjoin a crime or vice, or to forbid an act of prudence or benevolence, it is figurative. "Except ye eat the flesh of the Son of man," says Christ, "and drink His blood, ye have no life in you." This seems to enjoin a crime or a vice; it is therefore a figure, enjoining that we should have a share in the sufferings of our Lord, and that we should retain a sweet and profitable memory of the fact that His flesh was wounded and crucified for us. (Augustine, On Christian Doctrine, III.)
He admitted him to the Supper in which He committed and delivered to His disciples the figure of His Body and Blood. (Augustine, on Psalm 3.)
We have received a memorial of this offering which we celebrate on a table by means of symbols of His Body and saving Blood according to the laws of the new covenant. (Eusebius of Caesarea, Demonstratio Evangelica.)
To You we offer this bread, the likeness of the Body of the Only-begotten. This bread is the likeness of His holy Body because the Lord Jesus Christ, on the night on which He was betrayed, took bread and broke and gave to His disciples, saying, “Take and eat, this is My Body, which is broken for you, unto the remission of sins.” (Anaphora, quoted in Jurgens W, The Faith of the Early Fathers, II, p 132.)
Offer the acceptable Eucharist, the representation of the royal body of Christ. (Constitutions of the Holy Apostles.)
Certainly the sacraments of the Body and Blood of Christ that we receive are a divine reality, because of which and through which we are made sharers of the divine nature. Nevertheless the substance or nature of bread and wine does not cease to exist. And certainly the image and likeness of the Body and Blood of Christ are celebrated in the carrying out the Mysteries. (Pope Gelasius, de Duabus Naturis).
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