“Do what thou wilt shall be the whole of the Law.”
Chapter I Verse 40 in Liber AL vel Legis, Book of the Law

“Yet deeper drives ‘Do what thou wilt’; subconscious oppositions are evoked to visible appearance. The secret sanctuaries of the soul are cleansed. ‘Do what thou wilt’ purges his every part. He has become One, one only. His Will is consequently released from the interference of internal opposition, and he is a Master of Magick. But for that very reason he is now utterly impotent to achieve anything that is not in absolute accordance with his Original Oath, with his True Will, by virtue whereof he incarnated as a man.”
Chapter 16, Part I Of the Oath in Magick in Theory and Practice by Aleister Crowley.

“it does not mean surrendering to every whim, but rather the reverse. It involves finding out Who you are, and why you came into this world, and never swerving a hair’s breadth from that Will.”
— “Thelema” in Equinox III:10 by Aleister Crowley