But we see him who for a little while was made lower than the angels, namely Jesus, crowned with glory and honor because of the suffering of death, so that by the grace of God he might taste death for everyone. (Hebrews 2:9 ESV)
For it is impossible for the blood of bulls and goats to take away sins. (Hebrews 10:4 ESV)
Payment for Sins
I know of a man who attempted to pay off a large debt to a bank by trying to give the bank hay bales. It did not work.
I know of a man who attempted to pay off a large debt to the US government by trying to give the IRS a deed to a piece of property. It did not work.
I know of a man who attempted to pay off a large credit card debt by trying to give the credit card company a small percentage of the amount owed. It did not work.
Sin causes a debt to God. And that debt is our lives. (Romans 6:23)
The sacrifices of the Old Testament did not actually pay for any sins. They were accepted by God as an offering to teach us that at one point, an offering WOULD be accepted. An offering not of animals, but of a perfect human.
The sacrifice of a perfect, sinless human would be accepted by God in place of another human.
If Jesus was only human when He died on the cross, He could have paid the debt of any other individual human being.
So one person could have been saved.
But because Jesus was also God, divine, infinite as well as perfectly human, His death could count for more.
In fact His death was enough for every human who believes.
If it were not for the incarnation, Christ being BOTH human and divine… we would not have been saved. We could not have been saved.
We would still have to die for our sins.
But the incarnation makes salvation possible.