Leviticus 19:26
24 In the fourth year all its fruit will be holy, praise offerings to the Lord. 25 Then in the fifth year you may eat its fruit to add its produce to your harvest. I am the Lord your God. 26 “‘You must not eat anything with the blood still in it. You must not practice either divination or soothsaying. 27 You must not round off the corners of the hair on your head or ruin the corners of your beard.
1 Samuel 14:32
31 On that day the army struck down the Philistines from Micmash to Aijalon, and they became very tired. 32 So the army rushed greedily on the plunder, confiscating sheep, cattle, and calves. They slaughtered them right on the ground, and the army ate them, blood and all. 33 Now it was reported to Saul, “Look, the army is sinning against the Lord by eating even the blood.” He said, “All of you have broken the covenant! Roll a large stone over here to me.”
Notes and References
"... Sacred literature from Ugarit and Mesopotamia, as well as Israel, identified blood as the life force of any animal. As such in Israelite tradition it belonged to the life-giver, the creator God Yahweh. Therefore the Israelites were prohibited from consuming meat which still contained blood. This sacred fluid had to be drained from the meat and “poured on the ground like water” so that it returned to the earth. In sacrificial contexts the blood was to be poured on the altar (see Lev 17:11-12). The prohibition against eating meat with the “blood still in it” in Leviticus 19:26 is tied to the injunction against participating in any form of divination or sorcery. Thus, rather than a dietary law, this decree involves the practice of draining blood from a sacrificial animal into the ground or a sacred pit, which was designed to attract the spirits of the dead (see 1 Sam 28:7-19) or chthonic deities, and to consult them about the future. Such practices are found in several Hittite ritual texts and in Odysseus’s visit to the underworld (Odyssey XI, 23-29, 34-43). These practices were condemned (Deut 18:10-11) because they infringed on the idea of Yahweh as an all-powerful God, who was not controlled by fate ..."
Walton, John H. The IVP Bible Background Commentary: Old Testament (p. 302) InterVarsity Press, 2000