Hebrews 10

In the Old Testament, the people must give different sacrifices in different situations and they would need to make them again later.  These sacrifices also were only for the Hebrew people.  Christ's sacrifice covered over all the sins, was needed only once, and was for all people.  Before Christ died, only the high priest could go into the holy of holies.  Now, we can all come before God in prayer, Christ sacrifice was and is superior.