'Atonement' in the Bible

But Aaron and his sons offered upon the altar of the burnt offering, and on the altar of incense, and were appointed for all the work of the place most holy, and to make an atonement for Israel, according to all that Moses the servant of God had commanded.

Then David gave his son Solomon the plans for the portico of the temple and its buildings, treasuries, upper rooms, inner rooms, and a room for the mercy seat.