Carl Friedrich Keil and Franz Delitzsch Old Testament Commentary
The fat of cattle that had fallen (נבלה), or been torn to pieces (viz., by beasts of prey), was not to be eaten, because it was unclean and defiled the eater (Lev 17:15; Lev 22:8); but it might be applied "to all kinds of uses," i.e., to the common purposes of ordinary life. Knobel observes on this, that "in the case of oxen, sheep, and goats slain in the regular way, this was evidently not allowable. But the law does not say what was to be done with the fat of these animals." Certainly it does not disertis verbis; but indirectly it does so clearly enough. According to Lev 17:3., during the journey through the desert any one who wanted to slaughter an ox, sheep, or goat was to bring the animal to the tabernacle as a sacrificial gift, that the blood might be sprinkled against the altar, and the fat burned upon it. By this regulation every ordinary slaughtering was raised into a sacrifice, and the law determined what was to be done with the fat. Now if afterwards, when the people dwelt in Canaan, cattle were allowed to be slaughtered in any place, and the only prohibition repeated was that against eating blood (Deu 12:15-16, Deu 12:21.), whilst the law against eating fat was not renewed; it follows as a matter of course, that when the custom of slaughtering at the tabernacle was restricted to actual sacrifices, the prohibition against eating the fat portions came to an end, so far as those animals were concerned with were slain for consumption and not as sacrifices. The reason for prohibiting fat from being eaten was simply this, that so long as every slaughtering was a sacrifice, the fat portions, which were to be handed over to Jehovah and burned upon the altar, were not to be devoted to earthly purposes, because they were gifts sanctified to God. The eating of the fat, therefore, was neither prohibited on sanitary or social grounds, viz., because fat was injurious to health, as Maimonides and other Rabbins maintain, nor for the purpose of promoting the cultivation of olives, as Michaelis supposes, nor to prevent its being put into the unclean mouth of man, as Knobel imagines; but as being an illegal appropriation of what was sanctified to God, a wicked invasion of the rights of Jehovah, which was to be punished with extermination according to the analogy of Num 15:30-31. The prohibition of blood in Lev 7:26, Lev 7:27, extends to birds and cattle; fishes not being mentioned, because the little blood which they possess is not generally eaten. This prohibition Israel was to observe in all its dwelling-places (Exo 12:20, cf. Lev 17:10), not only so long as all the slaughterings had the character of sacrifices, but for all ages, because the blood was regarded as the soul of the animal, which God had sanctified as the medium of atonement for the soul of man (Lev 17:11), whereby the blood acquired a much higher degree of holiness than the fat.
John Gill Bible Commentary
For whosoever eateth the fat of the beast, of which men offer an offering made by fire unto the Lord,.... As oxen, sheep, rams, goats; meaning not only the fat of those that are offered, but the fat of all those of the like kind:
even the soul that eateth it shall be cut off from his people; See Gill on Lev 7:20 Maimonides (n) observes, that the punishment of cutting off is enjoined for the eating of fat, because men used to count it delicious, for which reason also God would honour his sacrifices with it: and he further observes (o), that the fat of the intestines too much saturates, hinders concoction, generates gross and frigid blood, hence it is much better it should be burnt than eaten; and that blood and what dies of itself are of difficult digestion, and of bad nourishment, wherefore the latter is forbidden in the Lev 7:24, and the former in Lev 7:26, of the punishment for eating fat, the same writer (p) observes, he that eats fat the quantity of an olive, presumptuously, is guilty of cutting off; if ignorantly, he must bring the fixed sin offering: and elsewhere (q) he says, he that eats fat is beaten for it; and he eats it a second time, and is beaten for it; but if he eats it a third time they do not beat him, but put him into a prison, which is a strait place according to his height, where he cannot stand upright, nor can he lie down in it; and they give him bread and water of affliction till his bowels are distressed, and he become sick, and then they feed him with barley till his belly bursts.
(n) Moreh Nevochim, par. 3. c. 41. (o) Ibid. c. 48. (p) Hilchot Maacolot Asurot, c. 7. sect. 1. (q) Hilchot Sanhedrin, c. 18. sect. 4.
Tyndale Open Study Notes
7:24 Animals found dead had not been drained of their blood and were therefore unclean. Their fat was unfit to offer to the Lord and could not be eaten. However, it could be used for any other purpose, such as greasing cart axles, waterproofing animal hides, and other household uses.