A NOTE ON PENITENCE
"While Thelema holds to the principle that spiritual attainment requires effort and struggle, the concept of "penance" or "regretting" has little relevance to us. Our struggle is not against conventional notions of "sin," but against ignorance, illusion and distraction. Contrition, meekness and self-denial are useless weapons against such enemies-- it is the Four Powers of the Sphinx: Knowledge, Will, Courage and Silence, which we must call to our aid. The illusion of original sin has led the Christian churches away from the true significance of self-discipline-- it is our task to restore it.
The Christian Sacrament of penance was supposed to effect the expiation of sins committed after the regeneration of baptism. The penitent, recognizing that he had committed a sin, confessed the sin to the priest (in the early church, the confession had to be made before the assembled congregation). He then declared his or her contrition and regret for having sinned, and requested absolution. The priest prescribed a penitential or ascetic activity, which the penitent was to perform as a token of repentance. If the penitent followed the priest's instructions, it was understood that the sin would be expiated through the mediatory prayer of the priest, and the penitent was free to continue his life with a clear conscience.
In Thelema, the negative concept of "sin" has given way to the positive concept of discovering and accomplishing one's True Will. As Liber XXX tells us, "Nevertheless have the greatest self-respect, and to that end sin not against thyself. The sin which is unpardonable is knowingly and willfully to reject truth, to fear knowledge lest that knowledge pander not to thy prejudices." The concept of expiation of sin has been transformed into that of perfection, which should be interpreted not as the achievement of a state of static flawlessness, but rather as an ongoing process whereby one's fitness for the task at hand (i.e. the accomplishment of the True Will) is increased."
~ Sabazius X*