I spent a week of my summer in a dungeon. More specifically, the travertine stones were styrofoam; it was Vacation Bible School (VBS), and I was Paul. (Barnabas as Paul, imagine that!) It felt natural to play the part, having lived a decade in modern Asia Minor planting churches and visiting and encouraging secret Christians. This VBS was special in that its theme was set in ancient Rome, and the 100 or so children learned what it was like to be in an underground church.

The first day when the children came to my prison cell, they saw me in chains with my very intimidating Roman guard, Brutus Flavius, standing nearby, and they began to treat our drama as if it were a melodrama, booing when the Roman guard spoke. It was rude, but it was their immature way of showing loyalty to me.

The next day, the VBS leaders spoke to the children and said, “Look, Brutus isn’t a Christian. Your job is to show him as much love as you can to make him curious about knowing Jesus.”

That was all those kids needed to hear. It was as if a switch went on in their heads. Obviously, my rough and grouchy guard was just acting, but those kids made it very hard for him to act grouchy! It became “hug a Roman” day. One child gave him a handwritten card of appreciation! Another boy, age five, who had been so frightened by the guard on the first night that he had cried, mustered his courage and came up and said, “Jesus loves you, Brutus.”

The next day the VBS leader had to speak again to the children. This time they had been mistreating the beggar in the marketplace. Again, the children rose to the occasion. She (the beggar) truly was a non-Christian—a purple-haired friend of a church member. The next day I overheard her saying to a friend, “I felt like a hero. Those kids really showed me a lot of love.”

It was impressive to me that simply relabeling these two people enabled the children to instantly shift their attitude about them. Immediately they took to the assignment of loving these costumed characters. They didn’t know how to fake love, so they undertook to love them for real.

How wonderful it would be if all adult believers could so easily be switched on to real-world marketplace witness! “You see that smoking, cursing, tattooed, obese woman shouting at her kids? She doesn’t know Jesus. Show her some love.” It could turn the world upside down if every time we saw some scary or unusual person, instead of thinking I should keep my distance, we thought I should love them.

Oh, the things you can learn from spending a week in a dungeon!

• Twitter