Genesis 9:4, God Allows Eating Meat, Part II of II
But flesh with the life thereof, which is the blood thereof, shall ye not eat.
//Yesterday I quoted the point in scripture where God changed his mind and allowed us to eat meat. It occurs just after the flood, when God changes his rule to let us kill and eat animals. But  why did God change his mind, and  what stipulation did he put on lifting the restriction?
The key is knowing that in antiquity, life was understood to reside in the blood. Today’s verse answers the second question: the stipulation is that the blood must be preserved and given back to God. That’s the idea behind Kosher slaughtering. This probably answers the first question too. God changed his mind because priests like to eat meat.
It is the priests who benefit from this law. It is they who set the rules of what could be killed and sacrificed (it seems God prefered those animals which are good to eat) and how they were killed (by bringing them to the priests, so the blood could be given back to God in sacrifice).
It’s a brilliant solution and a brilliant compromise. God is happy with the attention; the priests are happy with the free food; the rich who could own animals for food are happy if also a bit frustrated that all the slaughtering had to be done by the priests so they could get their share. Nobody consulted the animals on the matter, but their vote seems not to have mattered.