Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 185
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 185, with English translation by Maimonides (Rambam).
שלא לאכול חלב, שנאמר "כל חלב שור וכשב, ועז--לא תאכלו" (ויקרא ז,כג).
Not to partake of [hard] fat, as [Leviticus 7:23] states: "Do not eat any of the fat in an ox, sheep, or goat."