Deuteronomy 18:22

22 If a prophet speaks in the LORD's name and what he says doesn't happen or come true, then it didn't come from the LORD. That prophet has spoken on his own authority. Never be afraid of him.

Deuteronomy 18:22 Meaning and Commentary

Deuteronomy 18:22

When a prophet speaketh in the name of the Lord
Says he comes from God, is sent by him, and has a commission from him to say so:

if the thing follow not, nor come to pass;
as the prophecy of Hananiah, ( Jeremiah 28:3 ) that is the thing which the Lord hath not spoken; or otherwise it would have come to pass, unless when a condition is either expressed or implied, as the repentance or disobedience of a people; see ( Jeremiah 18:7-10 )

but the prophet hath spoken it presumptuously;
in a bold and daring manner, with great impiety and impudence, out of his own head and heart, being a mere device and imagination of his own, which, not having the fear of God, he delivered as coming from the Lord:

thou shall not be afraid of him;
not only to reprove him for his wickedness, but also to punish him for it; showing no regard to the high character he assumes, nor to the great pretensions he makes to sanctity, knowledge, and familiarity with God.

Deuteronomy 18:22 In-Context

20 But any prophet who dares to say something in my name that I didn't command him to say or who speaks in the name of other gods must die."

21 You may be wondering, "How can we recognize that the LORD didn't speak this message?"

22 If a prophet speaks in the LORD's name and what he says doesn't happen or come true, then it didn't come from the LORD. That prophet has spoken on his own authority. Never be afraid of him.