Deuteronomy 18:19-21

New Catholic Bible

¹⁹ I myself will call to account whoever does not heed my words that he will proclaim in my name. ²⁰ But if a prophet presumes to proclaim something in my name that I have not said to him, or he speaks in the names of other gods, that prophet is to be put to death.” ²¹ You might say to yourself, “How can we know that the Lord did not speak the message?”