Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 61
The full Hebrew text of Mishneh Torah, Positive Mitzvot, Chapter 61, with English translation by Maimonides (Rambam).
להיות כל קרבן בהמה תמים, שנאמר: "תָּמִים יִהְיֶה לְרָצוֹן" (ויקרא כב, כא).
For all animal offerings to be unblemished, as [Leviticus 22:21] states: "[When it is] unblemished, it will be desirable...."