That explains visions and prophecies. A vision is a preview of some future event that has not yet happened. It's just like a film clip God shows to His prophets of a scene that will come to pass in real life. It could be tomorrow, or thousands of years into the future. The prophet sees it now.
Spiritual dreams are the same sort of thing.
Sometimes God shows it in symbols. Sometimes it's an actual view of future events. The Bible's full of such visions. And condemn him at the judgment for rejecting God's Word and doing what he knew to be wrong. There's not an error in Scripture.