Q. 56: What is forbidden in the second commandment?
A. The second commandment forbids the worshiping of God by images, or any other way not appointed in His Word.
Take careful heed to yourselves, for you saw no form when the LORD spoke to you at Horeb out of the midst of the fire, lest you act corruptly and make for yourselves a carved image in the form of any figure: the likeness of male or female, the likeness of any animal that is on the earth or the likeness of any winged bird that flies in the air, the likeness of anything that creeps on the ground or the likeness of any fish that is in the water beneath the earth. And take heed, lest you lift your eyes to heaven, and when you see the sun, the moon, and the stars, all the host of heaven, you feel driven to worship them and serve them, which the LORD your God has given to all the peoples under the whole heaven as a heritage. Deuteronomy 4:15-19