The 29th prohibition is that we are forbidden from giving honorable treatment1 to a false prophet, or from refraining from executing him, since he says prophecy in the name of G‑d. Once we have determined his falseness,2 we should not fear punishment3 whatsoever.

The source of this commandment is G‑d's statement (exalted be He),4 "Do not fear him."

In the words of the Sifri, "The verse, 'Do not fear him,' teaches that one may not refrain from helping to convict him."

The details of this mitzvah have been explained at length in our Introduction to the Mishneh.