Hebrews 10:2

Otherwise, would they not have ceased offering them, because those who offered them, having once been purified, would have had no further consciousness of sins?

Hebrews 9:13-14

For if the blood of bulls and goats and a heifer's ashes sprinkling those who are ceremonially unclean purifies them with physical cleansing,

Hebrews 10:17

He continues to say: "I will never, never any more recall their sins and deeds of wrong."

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 continues to say: "I will never, never any more recall their sins and deeds of wrong."
Hebrews 9:13
For if the blood of bulls and goats and a heifer's ashes sprinkling those who are ceremonially unclean purifies them with physical cleansing,

General references

Hebrews 10:18
For when these are forgiven, there is no more need of an offering for sin.