Those directions which are given for the training of the moral feelings, as also those for concentration in thinking, for meditation — all this makes finally for the one goal of loosening the spiritual texture which binds together the physical and etheric bodies, so that the etheric body does not remain so firmly fitted into the physical body as it naturally is. All the exercises strive after this lifting out, this loosening, of the etheric body. […]
The efforts in concentrated thinking, according to the instructions given nowadays — and given also by the Rosicrucians — the efforts in meditation, the cleansing of the moral feelings: all these finally produce on the etheric body the effect described in my book, Knowledge of the Higher Worlds. As we use our eyes for seeing and our hands for grasping, so eventually we shall use the etheric body with its organs, but for looking into the spiritual, not the physical, world. The way in which we gather together and concentrate our inner life works for the independence of the etheric body.
Source: Rudolf Steiner – GA 131 – From Jesus to Christ: Lecture II – Karlsruhe, 6th October 1911
Translated by Harry Collison