Problem: God commanded Moses not to make “any carved image” (Ex. 20:4), lest it be used as an idol. Yet here Moses was commanded to “make a bronze serpent, and put it on a pole.” Later, the people worshiped this very image (2 Kings 18:4). Does not God command Moses to violate the very command He gave him against idolatry?
Solution: First of all, the command against making “carved images” was a command against making idols. God did not command Moses to make an idol for the people to worship but a symbol to which they could look in faith and be healed. Later, the people made this symbol into an idol. But this does not make the symbol wrong. After all, people have worshiped the Bible. This does not mean that the Bible was intended by God as an idol.
Further, not all “images” are idols. Religious art contains images but is not thereby idolatrous. God also instructed Moses to make cherubim (angels) for the ark, but they were not idols. There is a difference between a God-appointed representation of symbol (e.g., the bread and wine in the Lord’s Supper) and a man-made idol (see comments on Ex. 20:4).