Charles H. Spurgeon on Psalms 99:1

The cherubims. These were figures, or representations of angels, inclining their faces one towards the other, and touching one another with their wings. Ex 25:18. The use of these was to cover or overshadow the mercyseat with their wings, Ex 25:20, and from this seat God used to speak unto Moses, Ex 25:22; Nu 7:8-9. Which may be applied unto Christ, whose mediation was signified by the mercyseat;whence it is said, that he is a propitiation or covering mercyseat, Ro 3:25 1Jo 2:2 4:10, because by his obedience all our unrighteousness is covered. Thomas Wilson(-1621), in "A Complete Christian Dictionary, "1678.