Hebrews 7:27
He does not need to offer up [animal] sacrifices every day like those head priests did [Note: The head priest here is represented as being in charge of the daily sacrifices offered by the other priests], first for His own sins and then for the people's sins. For He did this once for all time when He offered up Himself [on the cross].
Hebrews 9:26
For then He would have had to suffer often since the creation of the world; but now at the end of the ages [i.e., the final period of world history] He has been revealed once [for all] to remove sin by sacrificing Himself.
Hebrews 10:1-10
For the law of Moses was [only] a foreshadow of the good things that [were] to come [i.e., in the Messianic age], not the exact image of those things. It can never, by the same sacrifices, continually offered year after year, make [morally] perfect those who draw near [to God in worship].