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. Hebrews 10:1

What is the purpose of The Law? Often we read or hear about Gods Law and wonder why did God institute this? Was this just a way for God to control us? No , as the scripture states “The Law was a shadow of the good things to come” You see we cant understand what sin is without The Law, and without Sin there is no understanding of why we need Jesus

Secondly once we recognize our sin from The Law, we can never be reconciled by The Law. Yearly atonement sacrifices were made for sin, but they could never fully satisfy the debt that we owe. The wages of our sins is death, and we need a transformation not just a substitution. 

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. Hebrews 10:2-4

Its interesting the author of Hebrews says the the sin sacrifices of the Old Covenant never forgave us for our sins, it was just a reminder of our sins. Only God alone can forgive your sin and cleanse it with His blood. The sacrificial rituals of the Old Covenant was just a reminder of our sinful state and how we need Jesus

Wherefore when he cometh into the world, he saith, Sacrifice and offering thou wouldest not, but a body hast thou prepared me: In burnt offerings and sacrifices for sin thou hast had no pleasure. Hebrews 10:5-6

This is why, Jesus came into this world, God became Flesh (John 1:14) to be the final sacrifice for our sins. The spotless Lamb of God , who never sinned, became our sin, so we might become righteous before God (2 Corinthians 5:21)