Hebrews 10:2

for then they would not have been repeated, because they who sacrificed being once purified, would not have been conscious of wanting any further atonement for their sins:

Hebrews 9:13-14

For if the blood of goats and of bulls, and the ashes of an heifer sprinkled on the unclean, can cleanse them from external impurities;

Hebrews 10:17

he adds, and their sins and iniquities will I remember no more."

Treasury of Scripture Knowledge

Summary

For then would they not have ceased to be offered? because that the worshippers once purged should have had no more conscience of sins.

General references

Bible References

Once

Hebrews 10:17
he adds, and their sins and iniquities will I remember no more."
Hebrews 9:13
For if the blood of goats and of bulls, and the ashes of an heifer sprinkled on the unclean, can cleanse them from external impurities;

General references

Hebrews 10:18
now where they are remitted, there is no need of any further oblation for sin.