Actually, you meet all kinds of people in prison. From very sincere to very shallow people. From very intelligent to pretty simple people. Some are pretty open to the Gospel, and some are not open at all.

One thing about it, there are always people that want to talk, and they are most always willing to talk about spiritual matters. So, going into a prison to witness is excellent practice. You can witness to more people in day than most Christians witness to in their life time, and that makes it easier to witness to people on the outside.