Thou shalt worship no other gods before me

Idolatry is something offensive to God. The Israelites were reprimanded for it. The reason idols are so offensive to God is that the one and only invisible and incomparable God is the only one who took on human flesh to save the world, and paid dearly for doing so, by suffering like no other. He alone deserves our sole honor and praise. He was an innocent man and did nothing to deserve being hung on the cross, but he did it anyway, for us, not himself.