So much of The Book of the Law deals directly or indirectly with morals that to quote relevant passages would be merely bewildering. Not that this state of mind fails to result from the first, second, third and ninety-third perusals!
"When Duty bellows loud 'Thou must!'
The youth replies 'Pike's Peak or Bust!'"
is all very well, or might be if the bellow gave further particulars. And one's general impression may very well be that Thelema not only gives general licence to do any fool thing that comes into one's head, but urges in the most emphatic terms, reinforced by the most eloquent appeals in superb language, by glowing promises, and by categorical assurance that no harm can possibly come thereby, the performance of just that specific type of action, the maintenance of just that line of conduct, which is most severely depreciated by the high priests and jurists of every religion, every system of ethics, that ever was under the sun!
You may look sourly down a meanly-pointed nose, or yell "Whoop La!" and make for Piccadilly Circus: in either case you will be wrong; you will not have understood the Book.
Shameful confession, one of my own Chelas (or so it is rather incredibly reported to me) said recently: "Self-discipline is a form of Restriction." (That, you remember, is "The word of Sin ...".) Of all the utter rubbish! (Anyhow, he was a "centre of pestilence" for discussing the Book at all.) About 90% of Thelema, at a guess, is nothing but self-discipline. One is only allowed to do anything and everything so as to have more scope for exercising that virtue.
Concentrate on "...thou hast no right but to do thy will." The point is that any possible act is to be performed if it is a necessary factor in that Equation of your Will. Any act that is not such a factor, however harmless, noble, virtuous or what not, is at the best a waste of energy. But there are no artificial barriers on any type of act in general. The standard of conduct has one single touchstone. There may be—there will be—every kind of difficulty in determining whether, by this standard, any given act is "right" or "wrong": but there should be no confusion. No act is righteous in itself, but only in reference to the True Will of the person who proposes to perform it. This is the Doctrine of Relativity applied to the moral sphere.
I think that, if you have understood this, the whole theory is now within your grasp; hold it fast, and lay about you!