Blood is the source of a creature's life.
A creature's internal source of life is found in its blood. This is obvious from simply observing everyday life. Blood flows throughout the body of humans and animals.
When the blood stops flowing, physical death occurs. When the body is emptied of blood, death occurs. In modern times, people donate blood to medical institutions which, in turn, use that donated blood to preserve and give new life to someone else.
The Bible affirms this basic life principle, as well. When GOD gave the Law of Moses to Israel, He included instructions regarding blood:
10 ‘And whatever man of the children of Israel, or of the resident aliens dwelling among you, eats any blood, I will set My face against that soul who eats blood and will utterly destroy him from among his people. 11 For the life of all flesh is in its blood, and I give it to you upon the altar to make atonement for your souls; for its blood makes atonement for the soul.’ 12 “Therefore, I said to the children of Israel, ‘No one among you shall eat blood, nor shall any resident alien who dwells among you eat blood.’ 13 Whatever man of the children of Israel, or of the resident aliens dwelling among you, hunts and catches any animal or bird that may be eaten, he shall pour out its blood and cover it with dirt; 14 for the life of all flesh is its blood. Therefore, I said to the children of Israel, ‘You shall not eat the blood of any flesh, for the life of all flesh is its blood. Whoever eats it shall be utterly destroyed.’
(Leviticus 17:10-14 OSB)
This simple truth has profoundly impacted human life and culture over the millenia. Future principles will illuminate why.