Deuteronomy 18:20 “But if any prophet presumes to speak anything in my name that I have not authorized 27 him to speak, or speaks in the name of other gods, that prophet must die. 18:21 Now if you say to yourselves, 28 ‘How can we tell that a message is not from the Lord?’ 29 – 18:22 whenever a prophet speaks in my 30 name and the prediction 31 is notfulfilled, 32 then I have 33 not spoken it; 34 the prophet has presumed to speak it, so you need not fear him.”
(from net.bible.org)
Of course, this passage can also be misinterpreted and lead to religious wars. However, I do wonder if we would get a few less doomsday predictions…
The phrase “That I commanded not” is actually a Hebraism. An idiom that expresses something negatively to affirm a positive. Weather that be something forbidden(like in Jeremiah 32:35) or contrary to stipulation(like in Leviticus 10:1). Both lying and taking God’s name(reputation) in vain is prohibited.
The word for Presumptuously is actually a pretty strong Hebrew word called Yadid(from zud or zid). A word that connotes arrogance and rebellion. In this case, someone who dares claim to be a spokesman for God but in reality is a lier and an imposture!
My bad. I meant the Hebrew word “Yazid”. Yadid means something completely different.:)