Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 15

שלא להדיח בני ישראל אחר עבודה זרה, שנאמר "לא יישמע על פיך" (שמות כג,יג); זו אזהרה למדיח.

Not to act as a missionary [madiach] to persuade the Jews to worship false gods], as [Exodus 23:13] states: "And the name of other gods... shall not be heard from your mouth." [Our Sages taught that] this is a prohibition against acting as a missionary for the worship of false gods.