The Holy Spirit, however, illuminates the Scriptures to make them understandable to believers. As some prophecies have been fulfilled, readers have a renewed appreciation of what the Bible predicted. False prophets were distinguished from true prophets by several factors, including whether the prophecies were fulfilled (Deut. 18:21–22). Usually there was some evidence that the message of a prophet of God was true; sometimes the prophets were verified by a miraculous sign. Attacks on the inspiration