Because Jesus Christ did what God wanted him to do, we are all purified from sin by the offering that he made of his own body once and for all.
Every Jewish priest performs his services every day and offers the same sacrifices many times; but these sacrifices can never take away sins. Christ, however, offered one sacrifice for sins, an offering that is effective forever, and then he sat down at the right side of God. There he now waits until God puts his enemies as a footstool under his feet. With one sacrifice, then, he has made perfect forever those who are purified from sin.