Luke 16:31 KJV — And he said unto him, If they hear not Moses and the prophets, neither will they be persuaded, though one rose from the dead.
Moses and the prophets was the Bible at the time.
They were and are the Word of God.
Abraham who believed God is a witness that persuasion comes through believing the Word of God.
If you doubt the seed, you’ll doubt the fruit of that seed.
The Word carries within it the conviction and persuasion you need to be bold in your posture of receiving the promise.