By Effie Caldarola | Catholic News Service

I blame Jesuit Father Greg Boyle for the fact that people sitting around me on an airplane a few years ago suspected I might be nuts.

I was reading Boyle's book, "Tattoos on the Heart," about his ministry with gang members in Los Angeles. Father Boyle is the founder of Homeboy Industries, a project that employs gang members, gives them marketable skills, and loves them and believes in them.

Father Boyle's book is a memoir of his kinship with his "homies," the many funerals at which he has officiated -- people he loved killing people he loved -- and the deep friendships he's made. He speaks tellingly of the incredibly troubled childhoods of the gang members he meets.

As I read, I found myself sniffling and wiping tears. Alternately, Father Boyle's sense of humor, and the humor he finds in his gang members, is hilarious. And his delivery is perfect. Suddenly, midflight, I would burst out laughing, tears still damp on my tissue.

People started to glance at me. I tried to be reserved, but "Tattoos" did me in. Instead of trying to stifle my emotions, I should have held up the book and proclaimed, "Buy this book. It will change you." 

Recently, I heard Krista Tippett's interview of Father Boyle on her program "On Being," which airs on National Public Radio. He has a new book out, "Barking to the Choir." As usual, humor plays a key role in his speaking and writing.

I was delighted to hear how Father Boyle described being attracted to the Jesuits as a young man protesting the Vietnam War. 

"They were a combo burger of absolute hilarity and joy," he told Tippett -- and "they were prophetic."

Someone asked me to write a reflection on Gaudete Sunday, the third Sunday of Advent. "Gaudete" means, literally, rejoice, and so I considered the subject of joy. I realized that like many people, I sometimes think of joy as an "if" and "when" proposition. Maybe, I wrote, when North Korea comes to the negotiating table, or if our loved one is cured, or we lose that last 10 pounds, we'll find joy.

But those life goals aren't the source of joy. Jesus is the source of joy. St. Paul tells us, "The one who calls you is faithful." That's cause for joy.

Pope Francis speaks of the necessity of joy. "There is no Christian without joy," he said in a homily last year. Joy through adversity is what separates the person of faith from those who can't see beyond this world's problems and darkness.

I know many activists, people engaged in great work for social justice and good causes. I've noticed that the ones who survive the longest, and do the best work, also have the best sense of humor. Not humor that grows from sarcasm or anger, but humor that grows from joy, a delight in others and a faith in the transcendent.

They're the ones -- the prophetic ones -- who believe that ultimately God's justice will prevail even if it seems bleak right now.

When we are tempted to let the world's problems get us down, or when we feel defeated in the work we do, it's time to pray, but also time to laugh. Laughter, like a meal, is best shared with others.

St. Ignatius, who founded the Jesuits, said we can find God in all things. Tough as it might be, we can also find joy -- and often some humor -- in all situations. Call it a combo burger, if you will, but faith and joy go hand in hand.