To not prophesy in the name of idolatry: To not prophesy in the name of idolatry — for example, he says that idolatry x commanded to worship it, and promises a reward for its worshipers and affrights the one who does not serve it with a punishment; as the prophets of Baal and Asherah would say, and like is mentioned in the books of the Prophets. And likewise included in this is if he says that God commanded to worship idolatry x. And the Scripture does not come about this with a specific clear warning, however the punishment of the one who prophesies in the name of idolatry is clear in the Scriptures — that he is liable for death, as it is stated about this (Deuteronomy 18:20), “and the one who speaks in the name of other gods, that prophet shall die.” And this death is strangulation, as we wrote adjacently. And we have already known the principle that they, may their memory be blessed, taught us, “He does not punish unless He warned.” And hence we shall say that the warning of this matter was included in “and the name of other gods shall you not mention” (Exodus 23:13), that we wrote in Parashat Mishpatim as a negative commandment of its own about another matter (Sefer HaChinukh 86). And it is not impossible for one negative commandment to prevent several things — and its law is not like the law of a general negative commandment, since the punishment of each and every matter is elucidated. This is the opinion of Rambam, may his memory be blessed (in the Sefer HaMitzvot, Shoresh 14 at the end).
From the laws of the commandment is that which they, may their memory be blessed, said (Sanhedrin 89a), “One who says, ‘Idolatry x said [or star y], “it is a commandment to do this” or “not to do [it],”’ even if he approximated the [correct] law, to render impure that which is impure and to render pure that which is pure, his verdict is death” — if volitional when there are witnesses and a warning, as is well-known in every place. [This] and the rest of its details are in Sanhedrin in the eleventh chapter.
שֶׁלֹּא לְהִתְנַבֵּא בְּשֵׁם עֲבוֹדָה זָרָה – שֶׁלֹּא לְהִתְנַבֵּא בְּשֵׁם עֲבוֹדָה זָרָה. כְּגוֹן שֶׁיֹּאמַר עֲבוֹדָה זָרָה פְּלוֹנִית צִוְּתָה לְעָבְדָהּ, וְתַבְטִיחַ גְּמוּל לְעוֹבְדֶיהָ, וְתַפְחִיד מֵעֹנֶשׁ לְמִי שֶׁלֹּא יַעַבְדָהּ. כְּמוֹ שֶׁהָיוּ אוֹמְרִים נְבִיאֵי הַבַּעַל וְהָאֲשֵׁרָה, כְּמוֹ שֶׁהֻזְכַּר בְּסִפְרֵי הַנְּבִיאִים. וְכֵן בִּכְלַל זֶה אִם יֹאמַר שֶׁהָאֵל צִוָּה לַעֲבֹד עֲבוֹדָה זָרָה פְּלוֹנִית. וְלֹא בָּא עַל זֶה בַּכָּתוּב בְּאַזְהָרָה מְבֹאֶרֶת מְיֻחֶדֶת בָּזֶה, אָמְנָם נִתְבָּאֵר בַּכָּתוּב עֹנֶשׁ הַמִּתְנַבֵּא בְּשֵׁם עֲבוֹדָה זָרָה, שֶׁהוּא חַיָּב מִיתָה, שֶׁנֶּאֱמַר עַל זֶה (דברים יח כ) וַאֲשֶׁר יְדַבֵּר בְּשֵׁם אֱלֹהִים אֲחֵרִים וּמֵת הַנָּבִיא הַהוּא. וּמִיתָה זוֹ הִיא חֶנֶק, כְּמוֹ שֶׁכָּתַבְתִּי בְּסָמוּךְ. וּכְבָר יָדַעְנוּ הָעִקָּר שֶׁהוֹרוּנוּ זִכְרוֹנָם לִבְרָכָה לֹא עָנַשׁ אֶלָּא אִם כֵּן הִזְהִיר, וְעַל כֵּן נֹאמַר שֶׁיִּהְיֶה אַזְהָרַת הָעִנְיָן הַזֶּה בִּכְלָל וְשֵׁם אֱלֹהִים אֲחֵרִים לֹא תַזְכִּירוּ (שמות כג, יג), שֶׁכָּתַבְנוּ בְּפָרָשַׁת מִשְׁפָּטִים לְלָאו בִּפְנֵי עַצְמוֹ בְּעִנְיָן אַחֵר (מצוה פו). וְאֵין בְּנִמְנָע לִהְיוֹת לָאו אֶחָד מוֹנֵעַ דְּבָרִים רַבִּים, וְלֹא יִהְיֶה דִּינוֹ כְּדִין לָאו שֶׁבַּכְּלָלוֹת מִכֵּיוָן שֶׁיִּתְבָּאֵר הָעֹנֶשׁ בְּכָל עִנְיָן וְעִנְיָן, זֶהוּ דַּעַת הָרַמְבַּ"ם זִכְרוֹנוֹ לִבְרָכָה (בספר המצות סוף שרש יד).
To not prophesy in the name of idolatry: To not prophesy in the name of idolatry — for example, he says that idolatry x commanded to worship it, and promises a reward for its worshipers and affrights the one who does not serve it with a punishment; as the prophets of Baal and Asherah would say, and like is mentioned in the books of the Prophets. And likewise included in this is if he says that God commanded to worship idolatry x. And the Scripture does not come about this with a specific clear warning, however the punishment of the one who prophesies in the name of idolatry is clear in the Scriptures — that he is liable for death, as it is stated about this (Deuteronomy 18:20), “and the one who speaks in the name of other gods, that prophet shall die.” And this death is strangulation, as we wrote adjacently. And we have already known the principle that they, may their memory be blessed, taught us, “He does not punish unless He warned.” And hence we shall say that the warning of this matter was included in “and the name of other gods shall you not mention” (Exodus 23:13), that we wrote in Parashat Mishpatim as a negative commandment of its own about another matter (Sefer HaChinukh 86). And it is not impossible for one negative commandment to prevent several things — and its law is not like the law of a general negative commandment, since the punishment of each and every matter is elucidated. This is the opinion of Rambam, may his memory be blessed (in the Sefer HaMitzvot, Shoresh 14 at the end).
שֹׁרֶשׁ הַמִּצְוָה בְּכָל עִנְיַן עֲבוֹדָה זָרָה יָדוּעַ.
The root of the commandment about all idolatry is well-known.
מִדִּינֵי הַמִּצְוָה. מָה שֶׁאָמְרוּ זִכְרוֹנָם לִבְרָכָה (סנהדרין פט, א) אֶחָד הָאוֹמֵר אָמְרָה לִי עֲבוֹדָה זָרָה פְּלוֹנִית, אוֹ כּוֹכָב פְּלוֹנִי, שֶׁמִּצְוָה לַעֲשׂוֹת כֵּן וְכֵן אוֹ שֶׁלֹּא לַעֲשׂוֹת, אֲפִלּוּ כִּוֵּן אֶת הַהֲלָכָה לְטַמֵּא אֶת הַטָּמֵא, וּלְטַהֵר אֶת הַטָּהוֹר, דִּינוֹ בְּמִיתָה, בְּמֵזִיד, כְּשֶׁיֵּשׁ עֵדִים וְהַתְרָאָה כַּיָּדוּעַ בְּכָל מָקוֹם. וְיֶתֶר פְּרָטֶיהָ, בְּסַנְהֶדְרִין בְּפֶרֶק אַחַד עָשָׂר.
From the laws of the commandment is that which they, may their memory be blessed, said (Sanhedrin 89a), “One who says, ‘Idolatry x said [or star y], “it is a commandment to do this” or “not to do [it],”’ even if he approximated the [correct] law, to render impure that which is impure and to render pure that which is pure, his verdict is death” — if volitional when there are witnesses and a warning, as is well-known in every place. [This] and the rest of its details are in Sanhedrin in the eleventh chapter.
וְנוֹהֵג אִסּוּר זֶה בְּכָל מָקוֹם וּבְכָל זְמַן, בִּזְכָרִים וּנְקֵבוֹת.
And it is practiced in every place and at all times by males and females.