Deuteronomy 18:18-22

18I will raise up for them a prophet like you from among their brothers. And I will put my words in his mouth, and he shall speak to them all that I command him. 19And whoever will not listen to my words that he shall speak in my name, I myself will require it of him. 20But the prophet who presumes to speak a word in my name that I have not commanded him to speak, or who speaks in the name of other gods, that same prophet shall die.’ 21And if you say in your heart, ‘How may we know the word that the LORD has not spoken?’— 22when a prophet speaks in the name of the LORD, if the word does not come to pass or come true, that is a word that the LORD has not spoken; the prophet has spoken it presumptuously. You need not be afraid of him.