This article is from http://www.mormonnewsroom.org/article/marriage
The Church of Jesus Christ of Latter-day Saints believes marriage is sacred and was ordained of God before the foundation of the world. This doctrine is laid out in a document of the Church called “The Family: A Proclamation to the World.” It states:
“The family is ordained of God. Marriage between man and woman is essential to His eternal plan. Children are entitled to birth within the bonds of matrimony, and to be reared by a father and a mother who honor marital vows with complete fidelity.”
For Latter-day Saints, marriage is eternal. The relationship between husband and wife does not have to end at death. This long-term perspective explains why the Church emphasizes marriage and family relations. Temple ordinances, Sunday worship, social activities and material resources all point to the well-being of the family. The Mormon community is only as strong as its homes. The family is the heart of society as well.
For millennia, strong families have served as the fundamental institution for transmitting to future generations the moral strengths, traditions and values that sustain civilization. Strong, stable families, headed by a father and mother, are the anchor of society. But not everyone chooses or has a chance to get married. Every family looks different, and society is strengthened whenever people commit to care for those under their charge.
Marriage is far more than a contract that ratifies the affections and obligations between a man and a woman. It is also designed to help parents rear children and teach them to become responsible adults. Throughout the ages, governments of all types have recognized marriage as essential in preserving social stability and perpetuating life.