Genesis 9:3

Lo! I have given you all things as the green herb to eat, but flesh in the blood thereof shall ye not eat; meaning this: Lately I interdicted you from eating many things, but now I permit you to eat of all things, and to eat even flesh. Sacrifice, therefore, and pour out the blood, and then eat the flesh as ye eat vegetables; and eat also of the olive, of which before the Flood it was not permitted to eat, because it also was the fruit of a tree

And He changed the food of men, giving them leave to eat flesh: for from Adam the first-formed until the Flood men ate only of seeds and the fruit of trees, and to eat flesh was not permitted to them. But since the three sons of Noah were the beginning of a race of men, God blessed them for multiplication and increase, saying: "Increase and multiply, and replenish the earth and rule it; and the fear and dread of you shall be upon every living thing of animals and upon all the fowls of the air; and they shall be to you for meat, even as the green herb: but the flesh with the blood of life ye shall not eat: for your blood also will I requite at the hand of all beasts and at the hand of man. Whoso sheddeth a man's blood, in return for his blood shall it be shed." For He made man the image of God; and the image of God is the Son, after whose image man was made: and for this cause He appeared in the end of the times that He might show the image (to be) like unto Himself. According to this covenant the race of man multiplied, springing up from the seed of the three.

Moreover, you were commanded to abstain from certain kinds of food, in order that you might keep God before your eyes while you ate and drank, seeing that you were prone and very ready to depart from His knowledge, as Moses also affirms: "The people ate and drank, and rose up to play." And again: "Jacob ate, and was satisfied, and waxed fat; and he who was beloved kicked: he waxed fat, he grew thick, he was enlarged, and he forsook God who had made him." For it was told you by Moses in the book of Genesis, that God granted to Noah, being a just man, to eat of every animal, but not of flesh with the blood, which is dead. And as he was ready to say, "as the green herbs," I anticipated him: "Why do you not receive this statement, 'as the green herbs,' in the sense in which it was given by God, to wit, that just as God has granted the herbs for sustenance to man, even so has He given the animals for the diet of flesh? But, you say, a distinction was laid down thereafter to Noah, because we do not eat certain herbs. As you interpret it, the thing is incredible. And first I shall not occupy myself with this, though able to say and to hold that every vegetable is food, and fit to be eaten. But although we discriminate between green herbs, not eating all, we refrain from eating some, not because they are common or unclean, but because they are bitter, or deadly, or thorny. But we lay hands on and take of all herbs which are sweet, very nourishing and good, whether they are marine or land plants. Thus also God by the mouth of Moses commanded you to abstain from unclean and improper and violent animals: when, moreover, though you were eating manna in the desert, and were seeing all those wondrous acts wrought for you by God, you made and worshipped the golden calf. Hence he cries continually, and justly, 'They are foolish children, in whom is no faith.'"