What does 1 Corinthians 7:4 mean when it says the husband and wife have authority over each other's bodies?
It means that in marriage neither spouse has exclusive authority over his or her own body; each has a mutual claim on the other. Paul places husband and wife on equal 50-50 ground, so each is responsible for the other's sexual needs and must not withhold the marriage bed to gain advantage.
Les teaches that 1 Corinthians 7:4 addresses the marriage relationship, and though Corinth's circumstances differ from ours, chapter 7 is increasingly appropriate as society crumbles into a similar social fabric. Paul says the wife does not have power over her own body, but the husband; likewise the husband does not have power over his own body, but the wife. That puts them on equal ground—a 50-50 relationship. Paul is talking about the satisfaction of the sexual needs of both parties. Verse 5 continues that since it is 50-50, the husband is to be aware of the wife's needs and the wife of the husband's needs, and they are not to defraud one another except by consent. Les notes that counselors warn never to use sex as a lever against a spouse: wives are not to withhold the marriage bed to gain an advantage, and vice versa. That is what Paul means.
The wife hath not power of her own body, but the husband: and likewise also the husband hath not power of his own body, but the wife.