Deuteronomy 18:18-22

18I will raise up for them a prophet from among their countrymen like you, and 1I will put My words in his mouth, and 2he shall speak to them everything that I command him.

193And it shall come about that whoever does not listen to My words which he speaks in My name, I Myself will 4require it of him.

20But the prophet who speaks a word 5presumptuously in My name, a word which I have not commanded him to speak, or 6which he speaks in the name of other gods, 7that prophet shall die.’

21And if you say in your heart, ‘How will we recognize the word which the Lord has not spoken?’

228When the prophet speaks in the name of the Lord, and the thing does not happen or come true, that is the thing which the Lord has not spoken. The prophet has spoken it 9presumptuously; you are not to be afraid of him.