Jamieson, Fausset and Brown on Exodus 20:4-5

4-5. Thou shalt not make ... any graven image ... thou shalt not bow down thyself to them--that is, "make in order to bow." Under the auspices of Moses himself, figures of cherubim, brazen serpents, oxen, and many other things in the earth beneath, were made and never condemned. The mere making was no sin--it was the making with the intent to give idolatrous worship.