Hell is not an easy subject to preach on. However, Jesus spoke about it often. I believe Jesus knew that hell was real and he wanted to make sure that every one else knew the reality of it as well.
I recently read a story about a pastor who did not believe hell was real and then discovered that it was real. I hope that you will take five minutes to read this story by clicking here.  The following is one of my favorite quotes from the pastor:

The main point I want people to take away is hell is real and it is really hard to stomach, but God loves us with such an amazing love that we have to tell people about that. Hell is not the point, heaven is the point. Loving people into heaven in a gracious and humble way.

He's exactly right. Our mission on earth is to expand the population of heaven. Loving God and loving others is God's way of making that happen.

Pastor Tim