The law required perfect obedience and pronounced a death sentence on any who broke it. Paul tells us that "the wages of sin is death . . ." (Romans 6:23 Romans 6:23For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.
American King James Version×).
Consider for a moment the penalty that each of us brought on ourselves by sin. It isn't purgatory or hell, or some other place or state of being or consciousness (request or download our free booklet Heaven and Hell: What Does the Bible Really Teach?). It is death— eternal oblivion, a nothingness, a total blotting out of existence from which we could never escape were it not for God's promise of the resurrection.
Paul continues in Romans 6:23 Romans 6:23For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.
American King James Version×, ". . . But the gift of God is eternal life in Christ Jesus our Lord." Since we all sin, the law can only demand our death. It has no provision for giving us eternal life. So how could anyone hope for life beyond the grave?
Jesus also fulfilled the law in the sense that He met the law's requirement by paying the penalty each of us incurred for disobedience, which is death. Jesus, who never sinned, never brought on Himself the death penalty that was required by the law. As our perfect sacrifice for sin, He was able to satisfy the law's demands that required our death. Thus He "put away sin by the sacrifice of Himself" (Hebrews 9:26 Hebrews 9:26For then must he often have suffered since the foundation of the world: but now once in the end of the world has he appeared to put away sin by the sacrifice of himself.
American King James Version×). Having "washed us from our sins in His own blood" (Revelation 1:5 Revelation 1:5And from Jesus Christ, who is the faithful witness, and the first begotten of the dead, and the prince of the kings of the earth. To him that loved us, and washed us from our sins in his own blood,
American King James Version×), Jesus makes it possible for us to receive God's gift of eternal life.
The "Law" section of the Bible, the five books of Moses, contains several kinds of laws. In addition to what we might call the moral laws that govern human behavior (such as the Ten Commandments), this section also contained various sacrificial laws requiring sacrifices for sin. Of themselves these laws and sacrifices could never remove the death penalty for sin (Hebrews 10:1-4 Hebrews 10:1-4  For the law having a shadow of good things to come, and not the very image of the things, can never with those sacrifices which they offered year by year continually make the comers thereunto perfect.
 For then would they not have ceased to be offered? because that the worshippers once purged should have had no more conscience of sins.
 But in those sacrifices there is a remembrance again made of sins every year.
 For it is not possible that the blood of bulls and of goats should take away sins.
American King James Version×).
"Consequently, when Christ came into the world, he said, 'Sacrifices and offerings you have not desired, but a body you have prepared for me . . .' . . . It is by God's will that we have been sanctified through the offering of the body of Jesus Christ once for all. . .When Christ had offered for all time a single sacrifice for sins, 'he sat down at the right hand of God,' . . . For by a single offering he has perfected for all time those who are sanctified" (Hebrews 10:5-14 Hebrews 10:5-14  Why when he comes into the world, he said, Sacrifice and offering you would not, but a body have you prepared me:
 In burnt offerings and sacrifices for sin you have had no pleasure.
 Then said I, See, I come (in the volume of the book it is written of me,) to do your will, O God.
 Above when he said, Sacrifice and offering and burnt offerings and offering for sin you would not, neither had pleasure therein; which are offered by the law;
 Then said he, See, I come to do your will, O God. He takes away the first, that he may establish the second.
 By the which will we are sanctified through the offering of the body of Jesus Christ once for all.
 And every priest stands daily ministering and offering oftentimes the same sacrifices, which can never take away sins:
 But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God;
 From now on expecting till his enemies be made his footstool.
 For by one offering he has perfected for ever them that are sanctified.
American King James Version×, NRSV).
What this is telling us is that Jesus fulfilled everything prescribed in the offerings for sin in the law of sacrifices. Jesus upheld the entire law by becoming the sacrifice for sin.
If Christ had not presented Himself as an offering for sin, the sacrifices that foreshadowed the "single offering for sins" would have constituted an unfulfilled prophecy or pledge, because they all pointed to Him.
Jesus said He came not to destroy the Law or the Prophets, but to fulfill them. He did so on several different levels and in several different ways. He showed the full spiritual intent of the law, living it perfectly as an example for us. The prophets had previously announced His person, His mission and many details of His birth, life, death and resurrection—which He fulfilled. The sacrifices of the law foreshadowed His sacrificial death for the sins of all mankind—which He alone could fulfill.
What Jesus was saying is that the Old Testament in all its parts and elements—moral and prophetic—referred to Himself and applied to Him. He fulfilled all aspects of what the Law and Prophets required, substantiating them and making good what they demanded and announced.