Deuteronomy 4:16

Lest ye corrupt... and make. — The connection between idolatry and corruption is twofold. First, it changes “the glory of the incorruptible God” into an image of His corruptible creatures. Secondly, it always ends in corrupting the idolater. Man was made to have dominion over the works of God’s hands. He cannot worship anything in creation, which he was not intended to rule. He can only fulfil his destiny when he strives after the Divine likeness, rising to that which is above him, instead of stooping to that which is below.

(17,18) Likeness of any beast... fowl... — There may be an allusion to the animal idolatry of Egypt here.