take the name of the Lord in vain (source).
Usually we think of this commandment as referring to expletives. But if someone makes a questionable claim that God told them this or that, are they also potentially violating this principle?
A young woman at our church, a recent convert, once came to some of us for advice. A young man had told her that the Lord had revealed to him that she was meant to be his wife. She felt no attraction to this guy, but she didn't want to rebel against the will of God. Those of us who had been in the church all our lives were able to tell her that that is one of the oldest lines in the book. "If God is really in it, He'll give you the vision, too, sister." That was a long time ago, and that woman is now married to the man that she fell in love with, not the guy who tried to play the God card.
Sometimes people start thinking that if they really, really want something, then God must want it, too. As Bible believers, we can say confidently that God wants stuff that is specifically outlined in scripture. But if we get very far from that, whether it's "God gave me a vision of your hair in waist-length braid extensions" (yes, a hairdresser really said that to a friend of mine) or "God told me to invade Iraq," we're getting into dangerous territory. The Lord will not hold a person guiltless who takes his name in vain.