Exodus 20:5-6

Thou shalt not bow down thyself to them, nor serve them: for I the LORD thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me; And shewing mercy unto thousands of them that love me, and keep my commandments.

 As with the previous two commandments we see that God wants us to keep him and only him on our minds. We should not pray or worship things or ideas that could be considered a God or an image of a God.