John Gill, on Isa 1:11

To what purpose is the multitude of your sacrifices unto me? saith the Lord,.... These people, though they neglected the weightier matters of the law, and the more substantial duties of religion, as did the Scribes and Pharisees in Christ's time, Mat 23:23 yet were very diligent in the observance of the ceremonial law, and repeated their sacrifices almost without number, on which they placed all their trust and dependence; wherefore, to take off their confidence in these things, the Lord observes to them the unprofitableness of them; they could be of no avail to them, for they could not expiate their sins, or atone for them; and they could not be profitable to God, for he had no need of them; see Psa 50:10. I am full of the burnt offerings of rams, and the fat of fed beasts; to the loathing of them, and therefore would no more eat their flesh, and drink their blood, or accept of them in sacrifice, Psa 50:13 "rams" were used for burnt offerings, Exo 29:18, Lev 1:10 and the fat of any creature offered in sacrifice was burnt, and forbidden to be eaten by men, Lev 1:8, Lev 1:15. and I delight not in the blood of bullocks, or of lambs, or of he goats: as he did in moral services, in acts of beneficence and mercy, and in sacrifices of praise and thanksgiving, Sa1 15:22, Hos 6:6 much less did he delight in the sacrifices of these creatures, as offered by such wicked hands and without faith in the blood and sacrifice of Christ; and still less when these were superseded and abrogated by Christ; for this prophecy belongs to the times of the apostles, as appears from Isa 1:9 see Psa 40:6. The several creatures mentioned were used in sacrifice, and their blood was sprinkled round about the altar, Lev 3:2 and before the vail, Lev 4:6.