After the fall of Adam & Eve, mankind’s relationship with God was severed. What had been a perfect relationship was now broken.
Romans 5:10 For if while we were enemies we were reconciled to God by the death of his Son, much more, now that we are reconciled, shall we be saved by his life.
Romans 5:1 Therefore, since we have been justified by faith, we have peace with God through our Lord Jesus Christ.
Without a perfect sinless sacrifice, that relationship could never be restored. While animal sacrifices and the law provided some degree of temporary relationship for God’s chosen people, it was woefully inadequate. Only through Jesus sinless life and sacrificial death – the perfect Lamb of God – was it possible for all mankind to be reconciled to God permanently. As sinful mankind, we deserve eternal separation from God. Instead, because of Jesus death, we have the privilege to have peace with God and reconciled to Him!