Among the class A texts or Holy Books of Thelema, I have found the following "Change not so much as the style of a letter"-warnings.
Such warnings in The Book of the Law:
Chapter I, 36.: "My scribe Ankh-af-na-khonsu, the priest of the princes, shall not in one letter change this book; but lest there be folly, he shall comment thereupon by the wisdom of Ra-Hoor-Khuit."
Chapter I, verse 54.: "Change not as much as the style of a letter; for behold! thou, o prophet, shalt not behold all these mysteries hidden therein."
Chapter II, verse 54.: "Nor shall they who cry aloud their folly that thou meanest nought avail; thou shall reveal it: thou availest: they are the slaves of because: They are not of me. The stops as thou wilt; the letters? change them not in style or value!"
--- [all emphasis by me]
Such warnings in The Vision and The Voice [This text contains both class A and class B material]:
The Cry of the 18th Aethyr, Which is Called ZEN:
"And an angel cometh forth, and saith: Be wary, for if thou change so much as the style of a letter, the holy word is blasphemed."[glow=red,2,300](*)[/glow] [...] "I wanted to go back to the King's Chamber. The Angel pushed me away, saying: "Thou shalt see these visions from afar off, but thou shalt not partake of them save in the manner prescribed. For if thou change so much as the style of a letter, the holy word is blasphemed." And this is the manner prescribed: ..." [...] "This shall be the form to be used by him who would partake of the mystery of any Aethyr. And let him not change so much as the style of a letter, lest the holy word be blasphemed."
The Cry of the 9th Aethyr, Which is Called ZIP:
"And the Angel cometh forth, ..." [...] "And he says, ..." [...] "And this shall be thy rule: ..." [...] "But thou, be thou eager and vigilant, performing punctually the rule. Is it not written, "Change not so much as the style of a letter"?"
[glow=red,2,300](*)[/glow] Aleister Crowley wrote the following about this first warning in his footnote number 4. to The Cry of the 18th Aethyr, Which is Called ZEN: "This warning is given directly."
--- [all emphasis by me]
Has anyone found any similar warnings in other class A texts or Holy Books of Thelema?
Well, the folly is let loose, for Therion seems to have failed to comment adequately thereupon in certain matters.
Give us an 'f', give us a 'k'. What's that spell !? Oh ? "f--k" ?? There appears to be a lacuna here in the original manuscript.
Guess the jury will have to remain out on this one. ::)