Isaiah 1:11,12

To what purpose, &c., your sacrifices unto me? Who am a Spirit, and therefore cannot be satisfied with such carnal oblations, but expect to be worshipped in spirit and in truth, and to have your hearts and lives, as well as your bodies and sacrifices, presented unto me. I delight not in the blood, &c. He mentions the fat and blood, because these were, in a peculiar manner, reserved for God, to intimate that even the best of their sacrifices were rejected by him. The prophets often speak of the ceremonies of Moses's law as of no value, without that inward purity, and true spiritual worship, and devotedness to God, which were signified by them. This was a very proper method to prepare the minds of the Jews for the reception of the gospel, by which those ceremonies were to be abolished. When ye come to appear before me Upon the three solemn feasts, or upon other occasions. Who hath required this at your hand? The thing I commanded was not only, nor chiefly, that you should offer external sacrifices, but that you should do it with true repentance, with faith in my promises, and sincere resolutions of devoting yourselves to my service.