The covenant of marriage makes a man and woman one flesh. Sex within marriage profoundly embodies and represents this one flesh reality. As such, it’s sacred and set apart for marriage among all human relationships, just as marriage is unique and sacred among all human relationships.
Paul points to the way in which sexual intercourse represents and embodies one flesh in his condemnation of sexual immorality. He makes it clear that this is part of the meaning of the Genesis “one flesh” passage (2:23–24): “Do you not know that he who is joined to a prostitute becomes one flesh with her? For as it is written, ‘The two will become one flesh’” (1 Cor. 6:16). Put more positively, Bible scholars agree that sexual intercourse is clearly tied to a one flesh marital union.
The one-flesh reality has implications for how married people are to view their bodies. Just as our bodies belong to Jesus Christ, who purchased us with his own blood, joining us to his body, the church (1 Cor. 6:15–20; Gal. 3:13), so the bodies of a husband and wife each belong to the other. Marital sex is perhaps the most profound and intimate way in which this powerful truth is lived out within our marriages (1 Cor. 7:3–4). Man and woman, united in the covenant of marriage, cleave together and yield their bodies to one another in love. This is beautiful, far more lovely than sex as we see it portrayed in most of modern culture today.
All of this means that sex within marriage is sacred, just as marriage itself is sacred. This doesn’t mean that we have to approach it in exaggerated piety or super-spirituality. Sex between a husband and wife is earthy and physical, just as our bodies are. And yet the symbolism of marital sex is deeply spiritual.
