דברים, פרק י״ח, פסוק כ׳

True prophecy serves as the direct channel of communication between God and humanity, but this profound connection carries a significant risk of abuse. To protect the purity of the divine message, strict boundaries are established, placing immense responsibility on anyone claiming to speak on behalf of heaven or other supernatural forces.

This severe warning is specifically directed at individuals who have already established themselves as recognized prophets by performing a sign or wonder. Because the public already trusts them, their potential to mislead is dangerous. Conversely, an ordinary person who invents messages, but lacks a following, does not face the severe punishment detailed here [העמק דבר]. Furthermore, liability only falls upon someone who acts with premeditated, conscious malice [רלב״ג, ביאור יש״ר, אדרת אליהו]. A prophet who makes an innocent mistake or is misled by a deceptive prophetic spirit, such as the prophets of Ahab, is exempt from punishment by a human court [אור החיים].

There are two primary categories of false prophets. The first involves someone speaking falsely in God's name. This includes inventing messages that contradict the Torah, altering commandments, or predicting false futures [רלב״ג]. It also encompasses a prophet who receives a genuine divine message but succumbs to the temptation of adding personal explanations, presenting those additions as if they were spoken directly by God [ביאור שטיינזלץ]. The prohibition extends to issuing false legal rulings. Due to the gravity of such an offense, a false prophet is judged exclusively before the High Court of seventy-one judges [תורה תמימה, העמק דבר].

Another dimension of this first category involves stolen prophecy. A person may deliver a message that God actually commanded, but not to him. Taking a prophecy given to a colleague and presenting it as one's own—as Hananiah ben Azur did with the words of Jeremiah—constitutes false prophecy [רש״י, בכור שור, גור אריה, משכיל לדוד].

The second category involves a prophet who speaks in the name of other gods, claiming that a foreign deity or power sent him. Such an individual is liable for the death penalty even if he does not actively incite others to worship idols. Remarkably, this applies even if his teachings align perfectly with Torah law, accurately forbidding what is prohibited and permitting what is allowed [רמב״ן, רש״י, ביאור יש״ר]. The core crime lies simply in attributing power, authority, or knowledge of the future to an idol [רמב״ן, ביאור שטיינזלץ, בכור שור].

The prescribed punishment for these offenses is death. When a method of execution is not explicitly detailed, the standard legal principle dictates that it is strangulation administered by the court [רש״י, רמב״ן, מזרחי, תורה תמימה]. Typically, court-mandated executions are emphasized with a doubled expression of death. In this instance, a single expression is used because subsequent warnings explicitly instruct the judges not to fear convicting the false prophet. This additional command makes it clear that the execution must be carried out by a human court, rendering the usual double emphasis unnecessary [הכתב והקבלה, אדרת אליהו]. Consequently, a clear distinction is drawn between three types of prophets executed by a human court—those who prophesy what they did not hear, those who steal another's prophecy, and those who speak in the name of an idol—and three types who face death at the hands of heaven: a prophet who suppresses his own prophecy like Jonah, a person who disobeys a prophet, and a prophet who violates his own instructions [רש״י, מזרחי, ברטנורא].