Commentary for Deuteronomy 18:20

אשר לא צויתיו לדבר [BUT THE PROPHET WHO SHALL PRESUME TO SPEAK A WORD …] WHICH I HAVE NOT COMMANDED HIM TO SPEAK — but which I may have commanded his fellow-prophet to speak (Sanhedrin 89a),

AND HE THAT SHALL SPEAK IN THE NAME OF OTHER GODS — “even if [his false prophecy] corresponded to the law, prohibiting what is forbidden, and permitting what is permitted. HE SHALL DIE — by strangulation.” This is Rashi’s language from the Sifre.²¹¹Sifre, Shoftim 177-178. Now the intent thereof is not to state that if a person came and said, “In my dream I saw that Peor said to me that you should be heedful in observing the commandment of the palm-branch,” that he be liable to the death penalty — rather, in that case he is innocent. And if he said that you should do it [the commandment] in order to worship that abomination, then he is a false prophet who prophesies to worship an idol, and even if he were to say it in the name of G-d his punishment is stoning. But the case here is that he said “I saw Peor for he is god and he commanded not to eat the flesh of the swine.” Similarly, if he were to tell in its name that such-and-such [an event] is to happen, since he says that it is that worshipped object that speaks and does, decrees and fulfills, he is to be put to death by strangulation. Therefore, the Rabbis have said in the Gemara:²¹²Sanhedrin 89a. “‘He who prophesies in the name of an idol,’ means such as the prophets of Baal.” They are the ones who would say that Baal is god, just as it is written, If the Eternal be G-d, follow Him; but if Baal, follow him.²¹³I Kings 18:21. They used to prophesy in his name, Go up [to Ramoth-gilead], and prosper, for the Eternal will deliver it into the hand of the king,²¹⁴Ibid., 22:12. their intent being to say that Baal is the lord who has this glorified name, and it is he who will give Ramoth-gilead into the hand of [king] Ahab.

ואשר ידבר בשם אלוהים אחרים, “or who shall speak in the name of other deities, etc.” Rashi -searching for a reason why Moses needed to state the obvious,- writes that even if the false prophet tells the people only matters which conform to traditional halachah, he is still subject to the death penalty. (Based on Sifri) Nachmanides explains that what is meant (by the Sifri) is not that the “prophet” announces that in his dream the deity Pe-or had appeared to him and had told him that it was important to observe the commandment of the four species, as anyone who does not do so is guilty of the death penalty. There is no death penalty for such a statement by such a “would-be prophet.” What is meant is that the “would-be prophet” announces: “I have seen in my dream, Pe-or, who is the deity, and he commanded not to eat pig’s meat; or that such an impostor announces that he had been foretold in his dream certain events, such an impostor is guilty of the death penalty because he had made a point of describing the source of his information as being a deity whom he recognizes as such.