"He sacrificed for their sins once for all when he offered himself." - Hebrews 7:27
In the Old Testament God made a covenant with his people. That covenant included a system of sacrifices that pointed to the forgiveness of sins. But those sacrifices could not fully take away sin because, as Hebrews states later, “it is impossible for the blood of bulls and goats to take away sins” (Hebrews 10:4). Those sacrifices only pointed ahead to the one true sacrifice that was really needed: the shed blood of a perfect human being who could offer his own life in place of ours, and that person is Jesus Christ.
We could not pay for our own sins. The only way for us to be saved was for a sinless person to die willingly in our place, for our sake. And only Jesus Christ, who is fully God and fully human, could do that.
For a time, God established the role of priests to offer sacrifices for his people. The priests offered sacrifices from the people to God day after day as payment for sins. And once a year, the high priest would make atonement for everyone on the Day of Atonement.
But all of that ceremony pointed to the once-for-all sacrifice of Jesus, the great High Priest. As our text says, “He sacrificed for their sins once for all when he offered himself.” Once for all. Sacrifices for sin are no longer needed. His sacrifice is enough for all. In Jesus all our sins are atoned for.
What can we do to pay for our sins? Nothing. Jesus gave the ultimate sacrifice, once for all.