Deuteronomy 18:19-21

Darby Translation

¹⁹ And it shall come to pass that the man who hearkeneth not unto my words which he shall speak in my name, I will require it of him.

²⁰ But the prophet who shall presume to speak a word in my name that I have not commanded him to speak, or that shall speak in the name of other gods, that prophet shall die.

²¹ And if thou say in thy heart, How shall we know the word that Jehovah hath not spoken?