Atonement
Keper (כפר) means “to cover”. When used of sin it takes on the meaning of atonement. However, atonement does not modify its definition; rather, it is a specific use for the word “to cover”. It is not a word that is restricted to religious purposes.
Noah is instructed to cover the ark inside and out, Genesis 6:14. In expressing the aspect of recompense, Jacob sends many of his possessions before him to Esau seeking to make an atonement for stealing the blessing from their father, Genesis 32:18.
The ark of the covenant has on top of it the place of covering, often translated as the mercy seat. This is the place where the High Priest would make an offering of the blood of bulls and goats each year to cover the sins of Israel, Exodus 25:17. The Mosaic law made place for the covering of sins by gifts and the offering of a sacrifice, Exodus 29:36. However, the gifts and sacrifices could not make the one preforming the religious service clear concerning their conscience, Hebrews 9:9.
In the New Testament, atonement is expressed by propitiation. In Hebrews 9:5, we find a reference to the Mercy Seat in the Old Testament Temple, which is translated by a word meaning “a place of satisfaction” or “propitiation”. Christ propitiatory work relates to the righteousness of God because He deferred judgment on previously committed sins, Romans 3:25, and was for the sins of the whole world, 1 John 2:2. However, propitiation is not equivalent with salvation. When it comes to salvation, Christ did not make a covering for sins, He sent them away (ἄφεσιν), Colossians 1:14, and it is by His blood that our conscience is cleaned from dead works, Hebrews 9:14.