Wisdom of today (2) : A Yoga Sutra by Patanjali.

1. The higher and lower siddhis (or powers) are gained by incarnation, or by drugs, words of power, intense desire or by meditation.

"These powers are obstacles to the highest spiritual realization, but serve as magical powers in the objective worlds."

It might, therefore, be observed that (for the seeker after truth) incarnation, intense desire and meditation are the three permissible methods, and the only ones to be practised; drugs and words of power or mantric incantations are the tools of black magic and concern the lower powers.

The question might here be asked, is it not true that words of power and the use of incense form part of the ceremonies of initiation and therefore are used by initiates and aspirants. Certainly, but not in the sense understood here, or for the purpose of developing psychic powers. The Masters and their disciples use words of power in order to deal with the non-human existences, to invoke the aid of the angels, and to manipulate the building forces of nature, and they employ herbs and incenses in order to purify conditions, eliminate undesirable entities and so make it possible for those higher upon the ladder of evolution to make their presence felt. This is, however, a very different thing to their use in order to become psychic.

It is interesting to note here that the first cause producing the unfoldment of soul powers, whether higher or lower, is the great wheel of rebirth. This must ever be taken into account. Everyone is not yet at the stage where it is possible for him to unfold the powers of the soul. The soul aspect is still dormant for many because full experience and development of the lower nature has not yet been undergone. The forty years' wandering in the wilderness with the Tabernacle and the conquest of Canaan, had to precede the rule of the kings and the building of the Temple of Solomon. Lives must be passed before the body, or the Mother aspect, is so perfected that the Christ Child can be formed within the prepared vessel. It should also be remembered that the possession of the lower psychic powers is in many cases a symptom of a low stage of evolution and of the close association of their owner with the animal nature. This has to be outgrown before the higher powers can blossom forth.

http://www.light-weaver.com/LW-old/ys/aab_ys/patanjali-bk4-01.html

http://www.sacred-texts.com/hin/yogasutr.htm