Where did the concept of marriage come from?

Genesis 2:18, 24Then the Lord God said, “It is not good for the man to be alone. I will make a helper who is just right for him.” . . . This explains why a man leaves his father and mother and is joined to his wife, and the two are united into one.

Marriage has been God’s idea from the beginning of creation. He created the first man and woman as distinct individuals with different qualities. At the same time, he created a special relationship between them allowing the two can become one. The act of physical intimacy, shared exclusively and uniquely between a husband and wife, is the model for the unity that should be experienced in all aspects of the marriage relationship. Among Christians, the marriage relationship is also a picture of the intense spiritual intimacy that should exist between a person and God. Just as he is our only God; our spouse is our only mate. Just as we love God more than anyone or anything, we love our spouse more than any other person. Just as we are able to be completely vulnerable and intimate in our relationship with God; we are to share intimacy and vulnerability with our mate in a way that should not be shared with any other person. Because marriage is meant to be a clear picture of our relationship with God, he designed the marriage relationship to be exclusive and permanent, just as our relationship with him is exclusive and permanent.