Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 194
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 194, with English translation by Maimonides (Rambam).
שלא לשתות יין נסך, שנאמר "אשר חלב זבחימו יאכלו, ישתו יין נסיכם" (דברים לב,לח).
Not to drink wine used for idolatrous libations, as [Deuteronomy 32:38] states: "...who ate the fat of their sacrifices and drank the wine of their libations."