Hebrews 10:8-10 English Standard Version
8 When he said above, “You have neither desired nor taken pleasure in sacrifices and offerings and burnt offerings and sin offerings” (these are offered according to the law), 9 then he added, “Behold, I have come to do your will.” He does away with the first in order to establish the second. 10 And by that will we have been sanctified through the offering of the body of Jesus Christ once for all.
We must believe that the requirements for obtaining a right standing before God has changed from obedience of the law to obedience of faith. The establishment of righteousness is no longer via the law but in faith of what Christ did on the Cross.
All sin must be punished. The consequence of sin is death. (Romans 6:23) Those sacrifices within the law were not pleasing to God but pointed to one perfect sacrifice that would put an end to sin as a barrier between man and God. Sin had to be removed. It had to be replaced with something that pleased God, and satisfied His call for justice.
Hebrews 11:6 English Standard Version (ESV) And without faith it is impossible to please him, for whoever would draw near to God must believe that he exists and that he rewards those who seek him.
The standard for a right standing before God was changed from obedience to the law to faith in Christ. We must believe that Jesus Christ died on the cross to remove sin as a barrier to right relationship with God.
Romans 6:3 English Standard Version (ESV) Do you not know that all of us who have been baptized into Christ Jesus were baptized into his death?
Galatians 2:20 English Standard Version (ESV) I have been crucified with Christ. It is no longer I who live, but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me.
This is only possible if done by faith.
Ephesians 2:8 English Standard Version (ESV) For by grace you have been saved through faith. And this is not your own doing; it is the gift of God,