You must learn to work on your etheric body: I have already given you all kinds of methods for this, using water, the earth or the flame of a candle, etc. If, for example, you have a pain somewhere, you can concentrate mentally on your etheric body and send it beams of light of every colour, and it will know what to do to remedy the problem. It will act on your cells; like the plant-life of the earth, it will serve as a link to restore communications between heaven and earth, and the part that was ill will once more be enlivened.
The physical body is linked to the etheric body by what is known as the silver cord, and it is thanks to the etheric body that the physical body possesses both life and sensitivity. The silver cord has four branches, attached to four different points in the physical body: the first in the brain, the second in the heart, the third in the solar plexus and the fourth in the liver. These four points are, as it were, the germs or seeds of the four bodies: the physical, the etheric, the astral body or body of desire and the mental body.
When humans come to earth to begin a new incarnation, they bring with them these four germs, minute atoms given to them by the great spirits of light on high, the twenty-four elders and the angels that serve them, and on which are inscribed and recorded all the physical and psychic characteristics needed. These sublime beings have examined all their previous lives and everything they have ever done so that the germs they receive correspond exactly to what they need and deserve.
A human’s invisible bodies – the etheric, astral and mental – are formed according to the same laws and in exactly the same way as the physical body of a child is formed in its mother’s womb. As soon as the father’s seed enters the mother’s womb, a tremendous work begins of which the mother is unconscious. Unknown to her, the forces of nature set to work within her, bringing just the right amounts and the right kinds of building materials, which correspond exactly to the requirements of the germ. You could also compare the germ to the lines of force in the mineral realm that determine the patterns in which particles come together to form crystals.
Omraam Mikhaël Aïvanhov
Izvor Book 209, Christmas and Easter in the Initiatic Tradition