The Torah in Parashat Re’eh addresses the situation of somebody who claims to speak prophecy on behalf of an Aboda Zara (foreign god), and it commands, “Lo Tishma El Dibreh Ha’nabi Ha’hu” – “Do not listen to the words of that prophet” (Debarim 13:4).
When an alleged prophet claims to speak in the Name of G-d, there is a vetting process which must be followed. The prophet is asked questions and told to provide proof to verify his claims. However, the Torah here commands that once a prophet claims to speak in the name of an Aboda Zara, we are forbidden from paying any attention to him, or engaging him in any way. We are not allowed to ask him any questions, or give him any credence or any opportunity to substantiate his claims. His prophecy must be immediately and outright rejected.
The Sefer Ha’hinuch explains that the Torah forbids engaging in any sort of dialogue with such a person because one who speaks with him might be misled to accept his claims. Even if ultimately the individual who speaks with the false prophet dismisses his claims, nevertheless, he might, over the course of the conversation, momentarily consider the possibility that he is a true prophet, Heaven forbid. The Sefer Ha’hinuch writes that G-d does not want us to question the truth about G-d, or entertain doubts, for even a fleeting moment. He therefore forbids speaking with a prophet who claims to have received prophecy from a foreign deity, as such engagement might lead to a temporary legitimization of his claims, which we must avoid.
The Mishna in Pirkeh Abot (2:14) instructs, “Da Ma She’tashib La’apikoros” – that we must know how to respond to a heretic, to someone who embraces foreign beliefs and ideologies. Significantly, the Mishna does not instruct us to speak to such a person, but rather to know for ourselves how we respond to the heretics’ challenges to our faith. We should not be approaching people who reject our beliefs to discuss these matters with them, because over the course of discussion, we might end up conceding some points, or even temporarily considering the legitimacy of their arguments. As the Sefer Ha’hinuch here teaches us, we must not be open even momentarily to hear the arguments of foreign ideologies, and we must therefore avoid such conversations.
This command applies in all places and at all times, and is binding upon both men and women. As this prohibition is violated verbally, by expressing interest, asking questions, and so on, one is not liable to Malkut for transgressing this Misva, as Malkut are administered only when violating a command through an action.