It all goes back into the old testament. There is an invisible omnipotent yahweh and then there is some kind of divine manifestion yahweh who deals directly with humanity. It is all very weird. The two figures become so intertwined you are not sure who is what and what is who.
The new testament is the realization that Jesus is this second yahweh or whatever and the term LORD becomes as ambiguous in the new testament as in the old testament.
I have always thought the whole Jesus though Jehovah idea was kind of weak. It is also very similar to the Trinity which is kind of funny.