Genesis 9:4

But flesh with the life thereof, which is the blood thereof, shall ye not eat. Although the eating of flesh was permitted, yet a restriction is added to the concession, namely, that excluding flesh as food while the living blood was still coursing through the veins, whether this referred to pieces cut out of the living animal or to the eating of blood. This provision was added to prevent man's degeneration to coarse and brutal barbarism, or even savagery.