Critics have sometimes claimed that marriage is not that important to God. But interestingly, the Bible both begins and ends with a marriage. In fact, marriage is the defining metaphor God uses to illustrate His love for the Church, His “bride.”
The natural place to begin an investigation into what God thinks about marriage (and sex) is in Genesis 1 and 2, where scripture describes God’s creation of the world and everything in it. Here are nine truths about sex and marriage from the first two chapters in Genesis:
1. Sex and marriage are a creation of God. Sex is not the result of a blind, evolutionary process that lacks meaning and merely exists to propagate the species. Rather, God is the one who created sex with a purpose for how it is to be expressed and experienced. The first explicit attribute we learn about God in the Bible is that He is the Creator (Gen 1:1), which implies there is a purpose for what He creates, including sex.
2. People are created as gendered beings. Gender is not accidental to the creation story. Rather, God intentionally made human beings male and female (1:27-28) so they could populate the earth. The creation story emphasizes distinctions between day and night, land and sea, as well as male and female. Gender is fundamental to what it means to be human.
3. The biblical design for marriage is monogamy. The pattern in Genesis 2:24 is that a man leaves his household, which consists of his father and his mother, and then “clings” to his wife. When God called Adam to name the animals, “there was not found a helper fit for him” (2:20b). The clear implication is that Adam was looking for one partner. Populating the earth only requires one man and one woman. Although many biblical leaders embraced polygamy, the clear design for marriage is monogamy.
4. The two sexes are equal in value. Even though there is contrast between Adam and Eve (male and female), there is no hint of ontological superiority for the male. Both are equal image bearers of the divine (1:27). While egalitarians and complementarians differ over the roles of men and women in the family and church, both agree that men and women have equal value.
5. Marriage is an exclusive relationship. Genesis 2:24 says a man shall leave his father and mother. The Hebrew term for “leave” is a strong term that is often translated as “abandon” or “forsake,” and is sometimes used to indicate that Israel has forsaken the God of Israel for false gods (e.g. Deut 28:20). Richard Davidson explains: “This leaving also implies the exclusiveness of the relationship: husband and wife, and no other interfering party, are bone of each other’s bones, flesh of each other’s flesh.”
6. Marriage is meant to be permanent. According to Genesis 2:24, man will “hold fast” to his wife. The language of this same verse, “This at last is bone of my bones and flesh of my flesh,” expresses a marriage covenant vow. Holding fast and the one-flesh union indicate permanence in the relationship. Jesus affirmed the intended permanence for marriage (See Matt. 19:3-4).
7. Marriage is heterosexual. Both Genesis 1 and 2 indicate that marriage is gendered. The man leaves his father and mother and clings to his wife. While marriage entails much more than gender differences, it entails no less. Paul affirms that marriage is gendered (See Eph. 5:22-33).
8. One of the primary purposes of sex and marriage is procreation. After indicating that males and females are made in God’s image, Genesis indicates that they are to “Be fruitful and multiply and fill the earth.” Thus, one of the primary purposes of marriage is procreation. Not all couples can have children, for a variety of reasons, but part of the divine design for sex and marriage is procreation.
9. Sex is good and beautiful. Over and over again the author of Genesis 1 makes it clear that creation is good: “And God saw everything he had made, and behold, it was very good” (1:31). Sex is part of God’s original good creation. Sex is only bad when we abuse God’s intended design. But in the marriage relationship of one man and one woman, sex is meant to be experienced without fear, shame, or regret and is both good and beautiful.
 Richard M. Davidson, Flame of Yahweh: Sexuality in the Old Testament (Peabody, MA Hendricksen, 2007), 44.