I was involved in a Jail ministry for nearly 10 straight years. I recently discovered that one of the inmates with whom I was involved, is now serving time in a federal institution as a dangerous (sexual) offender. This inmate claimed to be a Christian. He is a pedophile.
While I was able to be of help to some of those with whom I was involved, The biggest pay off was what I learned as a result of my experience with them.
To benefit as I did it involves more than leading them to the Lord. It involves befriending them, and attempting to support them upon their release, by helping them reintegrate into society. Which if they are successful will require tools and/or skills which many of them do not possess. It can be quite an eye opener.
I pray that too will become your experience?