Deuteronomy 18:19-21

World English Bible

¹⁹ It shall happen, that whoever will not listen to my words which he shall speak in my name, I will require it of him. ²⁰ But the prophet who speaks a word presumptuously in my name, which I have not commanded him to speak, or who speaks in the name of other gods, that same prophet shall die.”

²¹ You may say in your heart, “How shall we know the word which Yahweh has not spoken?”