"Beloved, do not believe every spirit, but test the spirits, whether they are of God;…"

I'm sure I have commented on this passage before.  It is clear, concise instruction on how to tell good theology from bad.  Testing the spirits as it were. 

Many false prophets.  How do you tell the Godly from the ungodly?  That is a good question isn't it? 

Well Scripture made this one easy for us.  There have been many times when I have wondered "God, why don't you just come out and say it?".  From reading the Bible I now know why but it is still nice when God makes it simple.  This I think is one of those times.

1 John 4:1-3(NKJV)

Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world. 

By this you know the Spirit of God: Every spirit that confesses that Jesus Christ has come in the flesh is of God, 

and every spirit that does not confess that Jesus Christ has come in the flesh is not of God. And this is the spirit of the Antichrist, which you have heard was coming, and is now already in the world.

Could it be more simple than that? 

If they don't affirm the divinity of Jesus, then you don't want to be taking any other spiritual advice from them.  Plain and simple.  At least that is what this passages is telling me.