Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 97
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 97, with English translation by Maimonides (Rambam).
שלא ייתן מום בקודשים, שנאמר "מום לא יהיה בו" (ויקרא כב,כא); כלומר, לא תיתן בו מום.
Not to inflict a disqualifying physical blemish upon a consecrated animal, as [Leviticus 22:21] states: "It shall not have a blemish." This can be interpreted to mean: Do not inflict a blemish upon it.