הלכה על דברים 18:22

That we not fear from the killing of a false prophet: That we not fear from killing a false prophet (see Mishneh Torah, Laws of The Sanhedrin and the Penalties within their Jurisdiction 14:3) and that we not fear that there be any punishment to us from this. And even if he prophesied about the fulfillment of the commandments - since there is falsehood in his mouth, we do not [receive] a punishment for his death; but rather it is a commandment upon us [to kill him]. And about this is it stated (Deuteronomy 18:22), "do not be afraid from him." And the language of Sifrei Devarim 178 is "'Do not be afraid from him' - do not prevent yourself from advocating guilt for him."