What Counts as a Genuine Message from God?

Suppose Fred is a Christian who is facing a moral dilemma, and prays to God for advice. Now, we commonly suppose that some apparent messages from God are real, and others not. So how is someone like Fred to know which messages are really from God and which are not?

However, I think this way of thinking may presuppose a concept of God that is too anthropomorphic. Granted, if God exists He wouldn't have a bodily mouth or anything like that, and I think most reflective theists realize that. But once we set aside such a picture, if we grant that God created (and sustains) all things, what would the distinction between something's being a genuine message from God and its being a spurious one consist in?

Here it is tempting to think that, though God doesn’t speak with a bodily mouth, He still engages in some spiritual (immaterial) activity that we would perceive as a voice giving advice, or at least as a feeling that we should do such-and-such. This could be understood in different ways, of course, but if we interpret it as meaning that in order to give advice God has to do something outside of the normal course of nature, I think it is false. If all good things come from God, and the advice that Fred (thinks he) got through prayer was good moral advice, it seems it follows that the advice must have come from God in some sense. What Fred "heard" may be the result of natural processes rather that a miraculous, special revelation to him, but if one believes in Divine Providence, that need not make it any less of a message from God. For Fred's receiving that advice at that time, though by means of certain natural processes, could still on this view have been part of God's eternal plan. Arguably, all Fred really needs to know in order to tell that the message is genuine is that God exists, that God is benevolent, and that the moral advice he got was sound.