Deuteronomy 18:20-22

Contemporary English Version

²⁰ But if I haven't spoken, and a prophet claims to have a message from me, you must kill that prophet, and you must also kill any prophet who claims to have a message from another god.

Moses said to Israel:

²¹ You may be asking yourselves, “How can we tell if a prophet's message really comes from the Lord?” ²² You will know, because if the Lord says something will happen, it will happen. And if it doesn't, you will know that the prophet was falsely claiming to speak for the Lord. Don't be afraid of any prophet whose message doesn't come from the Lord.