It is said in the rule of the Nagual
"every living being, if he/she wishes for it, has received the power to look for an opening. For the Seer who sees the opening, or for the creatures able to cross into this opening, it is obvious that the Eagle has granted this gift to immortalize its consciousness. " ( Carlos Castaneda)
It is dangerous to develop the Essence without having worked on the pain-body. The supposed spiritual part of the pain-body develops and produces a real incoherence by seizing the opening necessary for the development of the Essence.
The opening is created by the knock of the Spirit, then the descent of the Spirit.
The active pain-body is vampiric, sucking up the available energy for the Essence. It bypasses the "vital fire", connected to the yellow, the zone of 'Seeing' (solar plexus), and the corresponding organs: liver and gall-bladder. It is the most fragile zone because it is the door to the outside: the connection with the second attention.
The Eagle feeds on consciousness, while the Essence, in its turn, is going to feed on our Tonal. It's by cleansing the island of the tonal, by which we mean getting rid of our neurotic behaviours, that the essence is going to develop. Man has to remember there is an Essence in him, to find the way back and nurture its growth. Man received the order to forget himself, then, to remember himself.
The teachings of the left side are there to tell the Essence; you exist, claim your place.
The teachings of the right side are there to make the shell aware of itself and to use it.
After death, the Essence returns immediately to the Energy.