Albert Barnes Commentary Ezekiel 41:18

"And it was made with cherubim and palm-trees; and a palm-tree was between cherub and cherub, and every cherub had two faces;" — Ezekiel 41:18 (ASV)

On the symbolism of the "cherubim," see the note on Ezekiel 1:1...

Every cherub had two faces—not as in Ezekiel 1:0, "four faces." The convenience of depiction on 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 permitted the deviation.