“You will laugh” (Luke 6:21) is the only time Jesus referred to laughter, but, but it is certainly not the only time he laughed. He went to many parties, and you don’t do that without laughing a lot. He told stories that made people laugh (e.g. the idea of a camel squeezing itself through a needle’s eye), and he likely laughed along with them as he told them. No doubt about it, Jesus laughed. 
Unfortunately, most of the portraits of Jesus do not show him laughing. But there is one depiction called “Jesus Laughing,” which friends gave to Jeannie and me in 1990. Every day since, that portrait has hung on a wall in our several homes. We see it all the time, and some days I pause to look at it more intently.
The importance of Luke 6:21 is that Jesus put laughter into our vision of life in the Kingdom of God. He did it in a way that brought immediate joy, and also in a way that gave inevitable hope. In fact, in 6:25, he warned people not to live so that only the present is humorous. That kind of limited laughter may bring about weeping later. Sometimes laughter is a sign that we have things in perspective.
Kingdom laughing not only gives us a lot to laugh about right now, but more…it assures us that even when we weep right now, sadness does not have the last word. Jesus laughing is not only about the funny things happening around us today, it is also his way of saying, “You ain’t seen nothin’ yet!” Joy is a keynote in eternity.
Years ago, I read that Thomas Merton said “the mark of a saint is the ability to laugh.”  John Wesley believed “sour godliness is the devil’s religion.” Across the ages, the link between holiness and happiness (eudaemonism) has been noted. When we are at our best, we know at soul-level that, indeed, there is a time for laughter (Ecclesiastes 3:4). Jesus set the pace. Let’s follow it.
 Elton Trueblood wrote a book about this, ‘The Humor of Christ’ (Harper & Row, 1975). My longtime friend and colleague, Donald Demaray, also emphasized Jesus’ humor and the importance of it in the Christian life. He wrote, ‘Laughter, Joy, and Healing’ (Baker Books, 1986).
 I have not found this exact quote in Merton’s writing, but I have found the sentiment many times. Jim Forest tells that the first time he saw Merton, he was on the floor laughing. The laughing Merton made a first and lasting impression on him.