Hell is not something we like to talk about, but the Bible has plenty to say about it.
Hell was not prepared for man, but rather for the devil and his angels. But our sins separate us from God, which heads us to hell also. Hell is prepared for spiritual beings, not physical bodies, so the punishment there will not burn up men's physical bodies. Whatever exactly the punishment of hell is, it will be forever--there is no hope of relief. No matter how bad our life here is, there is always at least a hope for relief--if not when we sleep, at least when we die (or so we think). Hell is a place of no hope!
Years ago I was talking to a man who didn't know a lot about the Bible--he was too polite to say no to a Bible study. He was living with a girl he was not married to and was quite comfortable in this relationship. I talked about his situation before God and that this lifestyle would send him to hell. When I finished he said, "well I guess I'll just have to go to hell." My reply was that he didn't know what hell was or he wouldn't say that. We turned to 4-5 scriptures that talked about hell and he was visibly shaken. Here was a man who knew practically nothing about God's Word but when he read about hell it shook him up. He agreed to study the next week, but by then the fear had passed and shortly after that they moved so I don't know what happened to them.
If this person could understand what the Bible says about hell and it frightened him, what about you and I? Are you frightened by hell? You should be.