Paul explains here, that the blood of bulls and goats could not forgive sin. That is why sacrifices were made on a regular basis. But, the price for all sin was paid by the blood of Jesus. Jesus did what no other priest was ever able to do. He offered a complete sacrifice, which means it never had to be repeated again. The offering that Jesus made on the cross provided Eternal Redemption for us.
(Read Hebrews 10:19)