This is why he's the mediator of a new covenant (which is a will): so that those who are called might receive the promise of the eternal inheritance on the basis of his death. His death occurred to set them free from the offenses committed under the first covenant.
References for Hebrews 9:15
When there is a will, you need to confirm the death of the one who made the will.
This is because a will takes effect only after a death, since it's not in force while the one who made the will is alive.
So not even the first covenant was put into effect without blood.
Moses took the blood of calves and goats, along with water, scarlet wool, and hyssop, and sprinkled both the Law scroll itself and all the people after he had proclaimed every command of the Law to all the people.
While he did it, he said, This is the blood of the covenant that God established for you.
References for Hebrews 9:20
And in the same way he sprinkled the meeting tent and also all the equipment that would be used in the priests' service with blood.
Almost everything is cleansed by blood, according to the Law's regulations, and there is no forgiveness without blood being shed.
So it was necessary for the copies of the heavenly things to be cleansed with these sacrifices, but the heavenly things had to be cleansed with better sacrifices than these.
Christ didn't enter the holy place (which is a copy of the true holy place) made by human hands, but into heaven itself, so that he now appears in God's presence for us.
He didn't enter to offer himself over and over again, like the high priest enters the earthly holy place every year with blood that isn't his.
If that were so, then Jesus would have to suffer many times since the foundation of the world. Instead, he has now appeared once at the end of the ages to get rid of sin by sacrificing himself.
People are destined to die once and then face judgment.
In the same way, Christ was also offered once to take on himself the sins of many people. He will appear a second time, not to take away sin but to save those who are eagerly waiting for him.