Deuteronomy 18:22 in the World English Bible
When a prophet speaks in the LORD’s name, if the thing doesn’t follow, nor happen, that is the thing which the LORD has not spoken. The prophet has spoken it presumptuously. You shall not be afraid of him.
Context
21 And if thou say in thine heart, How shall we know the word which the LORD hath not spoken?
22 When a prophet speaketh in the name of the LORD, if the thing follow not, nor come to pass, that is the thing which the LORD hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him.