The word לא (not) sometimes means a negation and sometimes means a warning. That is, whenever it is in a place where one might think it is a commandment, it could mean that it is a negation, as לא יבדיל (but shall not divide it asunder)⁵²⁷ means it is not necessary to divide, that one might think it is a commandment to divide the sin offering of the bird apart. As when Maimonides writes in Sefer HaMitzvot Chapter 8.

footnotes: ⁵²⁷ Leviticus 5:8.

And moreover, an imperative sometimes means permission. And Rabbi Ishmael and Rabbi Akiva disagree about this⁵²⁸ when it says לה יטמא (for her may he defile himself)⁵²⁹, לעולם בהם תעבודו (of them may you take your bondmen for ever)⁵³⁰, וקנא את אשתו (and he be jealous of his wife)⁵³¹.

footnotes: ⁵²⁸ Babylonian Talmud Sotah 3a. ⁵²⁹ Leviticus 21:3. ⁵³⁰ Leviticus 25:46. ⁵³¹ Numbers 5:14.

And thus, two statements that come one after another where the first is a warning and the second is an imperative that contradicts the warning – it is not a commandment, only permission. Like שלש שנים יהיה לכם ערלים..ובשנה החמישית תאכלו את פריו (three years shall it be as forbidden to you…But in the fifth year may you eat of the fruit thereof)⁵³².

footnotes: ⁵³² Leviticus 19:23-25.