Jamieson, Fausset and Brown on Exodus 25:18

18. two cherubim--The real meaning of these figures, as well as the shape or form of them, is not known with certainty--probably similar to what was afterwards introduced into the temple, and described in Eze 10:8-22. They stretched out their wings, and their faces were turned towards the mercy seat [Ex 25:20], probably in a bowing attitude. The prevailing opinion now is, that those splendid figures were symbolical not of angelic but of earthly and human beings--the members of the Church of God interested in the dispensation of grace, the redeemed in every age--and that these hieroglyphic forms symbolized the qualities of the true people of God--courage, patience, intelligence, and activity.