“Were these God-like men “mediums”, as the orthodox spiritualists will have it? By no means, if by the term we understand those “sick-sensitives” who are born with a peculiar organization, and who in proportion as their powers are developed become more and more subject to the irresistible influence of miscellaneous spirits, purely human, elementary, or elemental. Unquestionably so, if we consider every individual a medium in whose magnetic atmosphere the denizens of higher invisible spheres can move, and act, and live. In such a sense every person is a medium.
Mediumship may be either 1st, self-developed; 2nd, by extraneous influences; or 3rd, may remain latent throughout life. The reader must bear in mind the definition of the term, for, unless this is clearly understood, confusion will be inevitable. Mediumship of this kind may be either active or passive, repellent or receptive, positive or negative.
Mediumship is measured by the quality of the aura with which the individual is surrounded. This may be dense, cloudy, noisome, mephetic, nauseating to the pure spirit, and attract only those foul beings who delight in it, as the eel does in turbid waters; or, it may be pure, crystalline, limpid, opalescent as the morning dew. All depends upon the moral character of the medium.
About such men as Apollonius, Iamblichus, Plotinus, and Porphyry, there gathered this heavenly nimbus. It was evolved by the power of their own souls in close unison with their spirits; by the superhuman morality and sanctity of their lives, and aided by frequent interior ecstatic contemplation. Such holy men pure spiritual influences could approach.
Radiating around an atmosphere of divine beneficence, they caused evil spirits to flee before them. Not only is it not possible for such to exist in their aura, but they cannot even remain in that of obsessed persons, if the thaumaturgist exercises his will, or even approaches them. This is MEDIATORSHIP, not mediumship.
Such persons are temples in which dwells the spirit of the living God; but if the temple is defiled by the admission of an evil passion, thought or desire, the mediator falls into the sphere of sorcery. The door is opened; the pure spirits retire and the evil ones rush in. This is still mediatorship, evil as it is; the sorcerer, like the pure magician, forms his own aura and subjects to his will congenial inferior spirits.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 