Albert Barnes Commentary Deuteronomy 4:12

"And Jehovah spake unto you out of the midst of the fire: ye heard the voice of words, but ye saw no form; only [ye heard] a voice." — Deuteronomy 4:12 (ASV)

Hero worship exhibited itself in the practice of setting up images of human form as household gods (Penates, compare Genesis 31:19; Genesis 35:2), or as local and civic divinities: a practice forbidden by Deuteronomy 4:16.

Nature worship in its baser shapes is seen in the Egyptian idolatry of animals and animal figures, and is condemned in Deuteronomy 4:17-18; while its less ignoble flight, the worship of the sun, moon, and stars, is forbidden in Deuteronomy 4:19.

The great legislator may be regarded as, in the passage before us, taking a complete and comprehensive survey of the various forms of idolatrous and corrupt worship practiced by the surrounding Eastern nations, and as particularly and successively forbidding every one of them.