The word “Abrahadabra” is sacred to the religion of Thelema, otherwise known as Thelemic mysticism. Although Thelema as a certain belief originated with the theories and personal lifestyle of François Rabelais, it was further expanded by the noted occultist, and eccentric religious man Aleister Crowley. Crowley further developed Thelema, which was basically as a word, meant to mean “do what tthou wilt”, into an entire religious movement. The Thelemic religion was based on Rabelais’ ideals, though the word, translated from a Greek dialect, actually means “will”; in the sense of human free will, Thelema is regarded as the core of free will and the religion is an established belief in doing what pleases one most. Closely similar in these principles is LaVeyan Satanism, which revolves around worship of the self, and of free will.
The word first appeared in The Book of the Law, which is the Thelemic religion’s sacred text, comparable to Christianity’s Holy Bible. In th book, Crowley described mankind’s new Aeon, in which a form of the Egyptian god Horus was the new ruler. Abrahadabra was the magical formula which symbolized the new Aeon of mankind. However, Abrahadabra is not to be confused with the “Word of the Law of the New Aeon”, which is Thelema. Basically, Crowley replaced the C in Abracadabra with H, and stated that he learned the new spelling of the word through qabalistic methods, i.e., meditation, tarot, etc., and then later used the word throughout his many journals and publications.
Abrahadabra, according to Crowley and other noted occultists was a word that signified double meanings, such as the circle and the square, the rose and the cross, as well as pentagram and hexagram. It also represent the unity of Microcosm and Macrocosm, so it had a specific significance to Thelemic mysticism as a word of double power, and dual properties. The numerological value of the word is 418, which Crowley explains later in his works on Numerology.