( Exodus 25:17 ; 37:6 ; Hebrews 9:5 ) This appears to have been merely the lid of the ark of the covenant, not another surface affixed thereto. (It was a solid plate of gold, 2 1/2 cubits (6 1/3 feet) long by 1 1/2 cubits (2 2/3 feet) wide, representing a kind of throne of God, where he would hear prayer and from which he spoke words of comfort. --ED.) It was that whereon the blood of the yearly atonement was sprinkled by the high priest; and in this relation it is doubtful whether the sense of the word in the Hebrew is based on the material fact of its "covering" the ark, or derived from this notion of its reference to the "covering" (i.e. atonement) of sin.
Bibliography InformationSmith, William, Dr. "Entry for 'Mercyseat'". "Smith's Bible Dictionary".