“You may say in your heart, “How shall we know the word which Yahweh has not spoken?”
Deuteronomy 18:21 (WEB)
Context Reading
19It shall happen, that whoever will not listen to my words which he shall speak in my name, I will require it of him. 20But 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.” 21You may say in your heart, “How shall we know the word which Yahweh has not spoken?” 22When a prophet speaks in Yahweh’s name, if the thing doesn’t follow, nor happen, that is the thing which Yahweh has not spoken. The prophet has spoken it presumptuously. You shall not be afraid of him.