On the symbolism of the “cherubim” see Ezekiel 1:1 note ...
Every cherub had two faces - Not as in Ezekiel 1, “four faces.” Convenience of delineation upon a wall may have suggested the alteration. The cherubic devices on the curtains of the tabernacle Exodus 26:1; Exodus 36:8 were no doubt like the cherubim over the ark, of which we have no reason to suppose that each had “two faces.” The symbolic character here admitted of the deviation.