The difference between blue ray and green ray.

[anagogy]

Ra said it's dangerous to crystalize the blue ray with 3rd density body. Or something like that. Connecting a 3rd density body to blue-ray can cause something.

If you want my personal opinion of that very veiled statement by Ra, it is because linking blue ray energy with red/orange/yellow triad of energy is looking at self, with the pure spot light of brutal honesty and objectivity, without any compassion whatsoever.  Most people are not ready to see themselves as they really are.  For the most part, we have very very warped self images of ourselves.  Most people think they are "more evolved" than they really are. These same people will usually "play themselves down" when talking about themselves in public, but secretly (perhaps even unconsciously), will still view themselves as more evolved than they really are.  Seeing the truth of ourselves, without the eyes of self forgiving compassion can drive a person to suicide or psychosis very very easily.