Halakhah zu Dewarim 18:22
אֲשֶׁר֩ יְדַבֵּ֨ר הַנָּבִ֜יא בְּשֵׁ֣ם יְהוָ֗ה וְלֹֽא־יִהְיֶ֤ה הַדָּבָר֙ וְלֹ֣א יָב֔וֹא ה֣וּא הַדָּבָ֔ר אֲשֶׁ֥ר לֹא־דִבְּר֖וֹ יְהוָ֑ה בְּזָדוֹן֙ דִּבְּר֣וֹ הַנָּבִ֔יא לֹ֥א תָג֖וּר מִמֶּֽנּוּ׃ (ס)
Wenn ein Prophet im Namen des HERRN spricht, wenn das Ding nicht folgt oder sich nicht erfüllt, so ist es das, was der HERR nicht geredet hat; Der Prophet hat es anmaßend gesprochen, du sollst keine Angst vor ihm haben.
Sefer HaChinukh
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."
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