Treasury of Scripture Knowledge

Summary

And this shall be an everlasting statute unto you, to make an atonement for the children of Israel for all their sins once a year. And he did as the LORD commanded Moses.

Bible References

Once a year

Hebrews 9:7
but only the high priest could enter the inner part, and he but once a year, and never without taking some victim's blood, to offer on his own behalf and for the sins committed through ignorance by the people.
Hebrews 10:3
They really only serve to remind the people annually of the sins they have committed,