This is the first time in the Pentateuch where “fat” appears in connection with “blood” (see Leviticus 7:33; Leviticus 17:6). It was believed that life is in the blood, and since God is the source of life, the blood must be returned to him. The burning of the fat and the sprinkling of blood against the altar signified the giving of the life of the animal back to the Lord upon its death.
17 It shall be a statute forever throughout your generations, in all your dwelling places, that you eat neither fat nor blood.”