Charles Spurgeon Commentary Exodus 20:4-6

"Thou shalt not make unto thee a graven image, nor any likeness [of any thing] that is in heaven above, or that is in the earth beneath, or that is in the water under the earth. Thou shalt not bow down thyself unto them, nor serve them, for I Jehovah thy God am a jealous God, visiting the iniquity of the fathers upon the children, upon the third and upon the fourth generation of them that hate me, and showing lovingkindness unto thousands of them that love me and keep my commandments." — Exodus 20:4-6 (ASV)

Here we are forbidden to worship God under any likeness whatsoever. The first command forbids the worship of another God; the second strictly forbids us to worship anything which our eyes can see, under the pretense that we are worshipping God in that way.

This is another offense, and much more common than the first; and it is often pleaded—"Oh, we do not worship these things: we worship God whom these represent." But here it is strictly forbidden to represent God under any form or substance whatsoever and to make that an object of worship.