In Judges 17:13, Micah (not the prophet) deluded himself in thinking that all was well when, in fact, it was not at all. Earlier in the chapter, the Holy Spirit tells us that each person had become, in essence, his own god. This not only does not bode well for the person, his family, but it also includes the community in which he lives. Micah thought he was doing that which was good. What he thought was good ending up costing him much. His idol god that he thought would protect was stolen – how ironic!
Sometimes we become deluded in thinking all is well when it is not. It is an easy thing for the mind to trap us into thinking such things. We think such things because we feel we know that our motivations are genuinely directed toward that which is good. The problem, however, is that which we define as good may not be good. In this context, there are two kinds of knowledge. First, the knowledge that originates with God, and second, the knowledge that originates with man. Micah chose the latter; which do you choose.