On the night in which our Lord Jesus Christ was betrayed, having taken bread and given thanks, he broke and gave it to his disciples, saying: Take and eat, for this is my body. Also having taken a chalice and given thanks, he said: Take and drink, for this is my blood. Since therefore he himself has declared and said of the bread, This is my body, who will dare thereafter to question? And since he himself has asserted and stated, This is my blood, who would doubt and claim that it is not his blood?
For which reason with complete assurance we take them as the body and blood of Christ. For in the form of bread is given to you his body, and in the form of wine is given to you his blood. And whenever you take the body and blood of Christ, you are made to be one in body and blood with him. In this way we are made to be bearers of Christ, his body and blood having been shared among his members. Thus have we become, according to St. Peter's words, sharers of the divine nature.
When once disputing with Jews Christ said: Unless you eat my flesh and drink my blood, you shall not have life in you. Since however they did not take spiritually what he was saying, they turned and went away offended, thinking that he was urging them to eat flesh. Under the old covenant there was bread of exposition each day in the Temple, but it came to its end with the old testament to which it pertained. Under the new testament, however, the bread is a celestrial bread and the drink a saving one, sanctifying souls as well as body. For just as bread suits the body, so does the Word befit the soul.
Attend not, therefore, to the bare ordinary elements in the eucharistic bread and wine, for according to the assertion of the Lord, they are the body and blood of Chirst. And even if sense presents that to you, yet let faith make you certain and sure. For you have been taught and imbued with faith most sure that what appears as bread is not bread, even though sensed so by taste, but rather is the body of Christ; and what appears as wine, and moreover is seen to taste so, is rather the blood of Christ, concerning which David said of old in the psalms: And the bread strengthens the heart of man, to gladden his face with oil. Strengthen your heart in taking that bread as spiritual bread, and gladden the face of your soul.
Having his face unveiled by your pure knowledge and contemplating the Lord's glory as in a mirror, may you go from glory to glory, in Christ Jesus our Lord, to whom be honor and power and glory for all ages. Amen.