"What to me is the multitude of your sacrifices? says the Lord; I have had enough of burnt offerings of rams and the fat of well-fed beasts; I do not delight in the blood of bulls, or of lambs, or of goats. When you come to appear before Me, who has required of you this trampling of My courts? Bring no more vain offerings; incense is an abomination to Me. New moon and Sabbath and the calling of convocations - I cannot endure iniquity and solemn assembly. Your new moons and your appointed feasts My soul hates; they have become a burden to Me; I am weary of bearing them. When you spread out your hands, I will hide My eyes from you; even though you make many prayers, I will not listen; your hands are full of blood."
- Isaiah 1:11-15
God isn't here rejecting the Mosaic ceremonies. He did, after all, command them Himself. Rather, He is angry with professing believers who continued to go through the motions of the ceremonies, but missed their point completely. The Apostle Paul referred to the same thing in II Timothy 3:5, "[people] having the appearance of godliness, but denying the power."
The ceremonies were never intended for their own sake; they aren't magic rituals that create spiritual miracles out of the thin air. Rather they were intended to reveal the holiness of God, His hatred of sin, and the necessity of atonement for it. As Hebrew 9:22 explains, "Indeed, under the Law almost everything is purified with blood, and without the shedding of blood there is no forgiveness of sins."
However, for the one who isn't numb to his own sins, the sacrifices should lead to a hatred of his sin, an appeal to the blood atonement, and the clear conscience that comes from knowing the Lamb who takes away the sins of the world (John 1:29). Again, we see in Hebrews 10:3-4, "But in these sacrifices there is a reminder of sin every year. For it is impossible for the blood of bulls and goats to take away sins."
So, what of the blood atonement for our sins? Is it never to be fulfilled? Are we left without the satisfaction of God's wrath? What freedom, what blessing to know that the atonement has been provided once for all! Hebrews 10:12-14, "When Christ had offered for all time a single sacrifice for sins, He sat down at the right hand of God, waiting from that time until His enemies should be made a footstool for His feet. For by a single offering He has perfected for all time those who are being sanctified." This verse disabuses the Church of Rome of its doctrine of the sacrifice in the mass: not only is that doctrine false, but it is a blasphemy against the once-for-all sacrifice of Christ on the cross.
When Israel performed their sacrifices as a formal ceremony, with no change of the heart, their consciences were clear, but Isaiah exposes that their peace was a deception. In contrast, for the one who truly places his faith in Christ, Hebrews 10:19-22 testifies, "Therefore, brothers, since we have confidence to enter the holy places by the blood of Jesus, by the new and living way that He opened for us through the curtain, that is, through His flesh, and since we have a great priest over the house of God, let us draw near with a true heart in full assurance of faith, with our hearts sprinkled clean from an evil conscience and out bodies washed with pure water."