Any perceived contradiction between different books or lectures by Samael Aun Weor should generally be decided in favour of the one with a later date – this is a criterion of precedence.
As with any other writer, the later books and lectures by Samael Aun Weor are more mature works than his earlier writings.
Throughout his life Samael Aun Weor went on writing and, at the same time, kept on working on himself to free his consciousness. As a result, he gradually became more objective in his judgement. This increased discernment is reflected in the quality of his teachings, which gradually became more synthetic and objective.
Some of his earlier assumptions were later disproved by his own experience, and then he corrected himself on those points. A dedicated student of his doctrine should have no difficulty in recognising this natural learning process.
Two erroneous beliefs found in early assumptions do merit, nonetheless, a warning to the neophyte:
Firstly, the belief that a celibate person, abstaining from sex, might just be able to awaken the kundalini by means of breathing exercises is a mistaken assumption that was soon corrected. Thenceforth, Samael Aun Weor spent much effort emphasising the fact that the Kundalini Fire is a sacred sexual fire and can only be awakened through devotional sexual magic. See, for instance, chapter 10 in Las Tres Montañas ("The Three Mountains").
Secondly, observance of a vegetarian diet stopped being recommended when Samael Aun Weor realised it was unhelpful. Although some specific esoteric practices do require a particular diet for a few days, or even an occasional fasting, a vegetarian or vegan diet does not, on the long run, aid self-realisation. Whilst the avoidance of meat is not a crime, a person seeking to follow the initiatic path of self-realisation needs to eat sufficient meat for its Fire element, which is necessary for sustained sexual potency. See, for instance, chapter 13 in El Misterio del Áureo Florecer ("The Mystery of Golden Blossoming").
This notwithstanding, earlier works should not be discarded, even if they may contain one or two glitches. "Not to throw the baby with the bath water" is obviously a sensible approach.
In spite of any errors, all such early works also contain wonderful pearls of wisdom, extremely valuable techniques and information, which are not repeated in later works.
For example, El Libro Amarillo ("The Yellow Book"), a vey early work, could be seen to contain both of the abovementioned errors, and yet Samael Aun Weor does, in his last book, Pistis Sophia Develado ("Pistis Sophia Unveiled"), which is the highest octave of his doctrine, refer the reader to El Libro Amarillo as a manual for the discipline of Jinn state.
It may seem incredible, but in the past a Gnostic organisation now sadly demised was restricted to a small number of the later books and lectures, retaining only as an oral tradition a few of the practices from the early works. Time has since proved this approach to be rather unhelpful.
A completely different matter is the misprints, typographical mistakes, and mistranslations that have sometimes slipped into the publication process. The spoken and written word of Samael Aun Weor has rightly been published by devoted amateurs. Despite their best intentions of service, typos and mistranslations do occur – to beware of them and learn to read Spanish would be the obvious advice.
The largest single typo we have witnessed persisted in the editions of Las Tres Montañas ("The Three Mountains") that were published by the aboventioned Gnostic organisation. Until its demise this group kept reprinting new editions with the last few paragraphs of chapter 20 missing. Check your own copy in case it is based on those.
A story sometimes heard is that at some point one other Gnostic organisation published Pistis Sophia Develado ("Pistis Sophia Unveiled") with editorial changes in the paragraphs about whether to change Hermetic Vessel. We have not personally seen a copy of such censored edition, but the point about the Hermetic Vessel is made in chapters 1 and 55. If this has been altered in your copy, then it is not the real work.
"I wish to tell you that these teachings for the new Aquarian age are being delivered in accordance with the law of the music octaves. Each one of these works is developed on a higher note. Once we reach the synthesis note, the Message will have concluded. After that, I will depart with my Divine Mother Kundalini towards eternity..."
Samael Aun Weor, My Return to Tibet (Christmas Message 1969-70)