Richard Chartres, Bishop of London, chose an inspirational challenge to open his homily at the wedding of William and Kate last month: “Be who God meant you to be and you will set the world on fire.” His message was that marriage is an extraordinary chance for two people to help each other to be far more than could ever be alone. He touched a deep chord of what families are about and why they are the bedrock of our society.

There’s nothing like the happiness of two people who truly, knowingly, and with a blend of confidence and humility, come together with a promise of love, committing themselves to a life together. It’s the epitome of hope and the finest of family caring. It’s creativity, solemnity and joy, all together.

The meaning of weddings is at my world’s center this week, as my precious daughter Laura looks to her marriage Saturday to her beloved Dan Ryan. What gives me the greatest joy is that indeed they bring out the best in each other – blending love of music and reading, nature and cooking, a commitment to helping others and to each other, humor and a feisty determination that, in the bishop’s words, sets the world on fire.

As Laura and I reflected on weddings, we both were acutely conscious of the blessings of their freedom of choice – the largest problems, indeed, are that their many friends cannot be part of a small wedding, and that the events rush by too fast. I came of age at a time when the ceremonial aspects of weddings tended to be disparaged, so the hooplah of a large event can seem jarring, but Laura reminds me that weddings across cultures and ages are indeed a life marker that is celebrated with verve and style. It’s for a reason: marriage is a testiment to the most fundamental human commitment.

But for too many people, the joys of marriage are an illusion. The Universal Declaration of Human Rights declares firmly that “Men and women of full age, without any limitation due to race, nationality or religion, have the right to marry and to found a family. They are entitled to equal rights as to marriage, during marriage and at its dissolution. Marriage shall be entered into only with the free and full consent of the intending spouses.” But these principles were not universally agreed on when the declaration was being discussed, and they are still contested in many settings. Marriage across racial and religious lines, today firmly accepted in our society, is still a life and death issue in many parts of the world. Freedom to marry a beloved partner of the same sex remains deeply divisive in our own society.

Perhaps most tragic, young children, especially girls, are married far too often. A UNICEF estimate puts the number of women aged 20–24 years who were married or in union before the age of 18 at 64 million.

Their parents may mean well, hoping to protect their daughters from violence, and to secure their future. But the evidence that underage marriage is devastating for girls, their children and their families is growing and compelling. Their risks of dying or suffering lifelong injuries in childbirth are high, they miss the chance at education and choice, and their children fare worse. The Elders group of distinguished statespeople has taken up this cause. What’s more, they are convinced that here is a place where religious leaders can and must play a central pastoral role in stopping a scourge that was understandable in the past but is inexcusable in the present.

Meanwhile, let us savor and rejoice in the wedding season, sharing in the hope and joy of marriages and celebrating their blend of freedom and commitment, sharing and private happiness, and diversity of styles and links to past and present. They set the world on fire.

Katherine Marshall is a senior fellow at Georgetown University’s Berkley Center for Religion, Peace and World Affairs, a Visiting Professor, and Executive Director of the World Faiths Development Dialogue.