All appearances of rainbow light are the natural clarity of one’s own awareness. All appearances of the manifestations of peaceful and wrathful wisdom deities are the natural form of one’s own awareness. All sounds are one’s own sound. All light is one’s own light. Have no doubt or second thoughts about this. If a doubt arises, one will be thrown into cyclic existence. If one decides that these are self-manifesting appearances, not wavering from clear emptiness, The Three Kayas will be attained, and that right there is Buddhahood. Even if one is thrown into cyclic existence, one will definitely not go there.

Thinley Norbu
A Cascading Waterfall of Nectar 
Shambhala Publications