Ps 49:13

“Why then dost still think of thy flocks? "Shall I eat the flesh of bulls, or shall I drink the blood of he-goats?" Ye have heard what of us He requireth not, who willeth to enjoin us somewhat. If of such things ye were thinking, now withdraw your thoughts from such things: think not to offer God any such thing. If thou hast a fat bull, kill for the poor: let them eat the flesh of bulls, though they shall not drink the blood of he-goats. Which, when thou shalt have done, He will account it to thee, that hath said, "If I shall be hungry, I will not tell thee:" and He shall say to thee, "I was hungry, and thou gavest Me to eat." "Shall I eat the flesh of bulls, or shall I drink the blood of he-goats?"”

“"Shall I eat?" Above, the Psalmist, in the person of the Lord, assigned the reason why the Lord will not accept goats, even if he were in need; here, however, he shows that he has no need. It should be known that in the law it is commanded that the flesh of holocausts be burned and that the blood be poured out at the base of the altar. And someone could suspect that God delighted in the blood and flesh of those animals. This was also the opinion of the pagans, that their gods delighted in the odors of flesh and the pouring out of blood, as Augustine says. And the Lord says that he does not delight in these things, which do not please in themselves. And therefore he says, "Shall I eat the flesh of bulls, or shall I drink the blood of goats?" As if to say: no, because I have no need, nor do I take delight in them, because I delight in those things which are in themselves the food of God. But the food of God is other than the flesh and blood of animals; for the food of God is that which is the food of all the saints. Lk. 22: "I dispose to you, as," etc. And thus the nourishment of the saints and of God is the same. But the saints are nourished by the very love of God; and thus God is nourished in the enjoyment of himself. Tob. 12: "I use invisible food and drink that cannot be seen by men."”