We do not have to read very much literature or talk to very many people before we find someone speaking as if God gives us His law because He wants to make sure we don’t have any fun. It is truly sad that so many people have this idea of the Lord, for He is no killjoy. In fact, one of the purposes of the law is to provide boundaries that keep us from getting hurt when we transgress them. Used rightly, the law is actually a means to help us celebrate life (Ps. 84:11).
The seventh commandment provides an excellent example of this principle. To understand this, we must look back to the very first marriage in history, between Adam and Eve. Genesis 2:18–25 explains that God made man and woman for each other, that He created marriage so that we would not be alone. In the marriage relationship, husband and wife come together as one flesh in a mystical union that images the union of Christ and His church (Eph. 5:31–32). Marriage was created so that man and woman could be together and be naked and unashamed (Gen. 2:25). The sense of this verse includes not only physical nakedness but points also to vulnerability in a broader sense. God’s purpose for marriage is that we would have a relationship in which we can be vulnerable to another person without fear or shame.
God forbids adultery in order to safeguard this relationship. When sin entered the world, it affected everything, including marriage, and the lust that now arises in our fallen hearts can tempt us to break our marriage vows. If a husband or wife commits adultery, he or she destroys the environment in which his or her spouse could experience vulnerability safely and benefit from the most profound union two people can enjoy with one another. Adultery causes such harm to the injured party and God is so concerned with protecting the innocent that adultery is one of the few grounds that are given for divorce in Scripture (Matt. 19:9). The innocent party in a situation where adultery has been committed is not obligated to divorce the offending spouse, and many are able to rebuild their marriage after it is devastated by sexual sin. But the innocent party may divorce the guilty spouse without committing sin.
Adultery is such a grievous sin and is so destructive of relationships that God compares idolatry to adultery in Ezekiel 16:1–58. The commandment against adultery reminds us of the seriousness of this sin and sets boundaries to preserve our well-being.