Q. 56: What is forbidden in the second commandment?
A.The second commandment forbids the worshipping of God by images, or any other way not appointed in His Word.
You shall not worship the LORD your God in that way; for every abomination to the LORD which He hates they have done to their gods; for they burn even their sons and daughters in the fire to their gods. “Whatever I command you, be careful to observe it; you shall not add to it nor take away from it. Deuteronomy 12:31-32