"In the interpretation of figurative passages, let the following canon be observed. If the passage be preceptive, either forbidding some flagitious deed and some heinous crime, or commanding something useful and beneficent: then such passage is not figurative. But, if the passage seems, either to command some flagitious deed and some heinous crime, or to forbid something useful and beneficent: then such passage is figurative. Thus, for example, Christ says: Unless ye shall eat the flesh of the Son of man, and drink his blood; ye shall have no life in you. Now, in these words, he seems to command a heinous crime or a flagitious deed. Therefore the passage is a figure, enjoining us to communicate in the passion of our Lord, and admonishing us to lay it up sweetly and usefully in our memory because, for us, his flesh was crucified and wounded. On the other hand, Scripture says: If thy enemy shall hunger, give him food; if he shall thirst, give him drink. Here, without all doubt, an act of beneficence is enjoined."

“The Lord ... said: Unless a man shall eat my flesh, he shall not have in himself eternal life. Certain of his disciples, the seventy to wit, were scandalised, and said: This is a hard saying; who can understand it? And they departed from him, and walked with him no more. His saying ... seemed to them a hard one. They received it foolishly: they thought of it carnally. For they fancied, that the Lord was going to cut from his own body certain morsels and to give those morsels to them. Hence they said: This is a hard saying. But they themselves were hard: not the saying. For, if, instead of being hard, they had been mild, they would have ... learned from him what those learned, who remained while they departed. For, when the twelve disciples had remained with him after the others had departed, ... he instructed them, and said unto them: It is the spirit that quickeneth; the flesh profiteth nothing. The words, which I speak unto you, are spirit and life. As if he had said: Understand spiritually what I have spoken. You are Not about to eat this identical body, which you see; and you are Not about to drink this identical blood, which they who crucify me will pour out. I have commended unto you a certain sacrament. This, if spiritually understood, will quicken you. Though it must be celebrated visibly, it must be understood invisibly.”