Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 50
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 50, with English translation by Maimonides (Rambam).
שלא לחון על עובדי עבודה זרה, שנאמר "ולא תחונם" (דברים ז,ב).
Not to show favor to the worshipers of false gods, as [Deuteronomy 7:2] states: "Do not show them favor."