Christ is the key

There were high priests in the Hebrew Scriptures, the system had forgiveness of sins on credit. The high priests and the people were in sin debt but Christ will and would take away all sins and he paid for the debt.
The high priests could never take away the sins of the people by dying on the cross and conquering death.
Jesus is God and only he can save.

Hebrews 5:1-4

 Every high priest is selected from among the people and is appointed to represent the people in matters related to God, to offer gifts and sacrifices for sins. ² He is able to deal gently with those who are ignorant and are going astray, since he himself is subject to weakness. ³ This is why he has to offer sacrifices for his own sins, as well as for the sins of the people. ⁴ And no one takes this honor on himself, but he receives it when called by God, just as Aaron was.