Exodus 29:13 - Coke's Commentary on the Holy Bible

All the fat that covereth the inwards— By the fat that covereth the inwards, is meant a fat, thin membrane, spread over the intestines, and fastened to the concave part of the liver, and named the omentum or caul. By the caul that is above the liver is meant, according to the LXX and others, the great lobe that is upon or by the liver. The caul was much used in ancient sacrifices; the Persians offered nothing but this to their gods. Calmet remarks, from Athenaeus, that the ancients ate the liver, covered with or enfolded in the caul; whence he thinks it probable, that the liver of the victim was, in like manner, wrapped up in the caul before they laid it upon the altar; and that this is what Moses means by the caul above or upon the liver. Some have thought that the fat, which is gross without sense and feeling; the liver, which is heavy, (and, indeed, has its name from thence in the Hebrew,) and to which the gall-bag, seat of envy and malice, is united, &c. are ordered to be burnt upon the altar, to teach men to mortify all gross, evil, and carnal affections. See Psalms 119:70. Deuteronomy 32:15.Colossians 3:5. See also Theodoret. quest. 61 in Exod. Ainsworth, however, and several after him, apprehend that as the fat sometimes signifies the prime of any thing, (Psalms 22:29; Psalms 81:16 in the original,) so its being offered upon the altar, might be to inculcate the duty of giving the best of every thing to God.