Marriage is a mystery: The Bible says that husband and wife become "one flesh," as head and body, in the likeness of Christ and the church. The husband is the head; the wife is the body. Together they project a spiritual image, a bizarre picture of a male-headed female body.

The language of "one flesh" and "head" is metaphorical, of course. And as Eugene Peterson wisely puts it, "A metaphor, instead of pinning down meaning, lets it loose. The metaphor does not so much define or label as it does expand."

But as metaphors expand into mystery, we become impatient, and we start reading into the metaphor things that are not there.

For example, it is often assumed that the word head means "leader"—though the Bible never says the husband is the "leader" of his wife. The mystery of one flesh is exchanged for a business model in which the husband is the boss and the wife his assistant.

In addition, many evangelicals assume that the husband is the head of the house. But the Bible does not say that. It says that the husband is the head "of the wife" (Eph. 5:23). He is the head of her. That makes sense in light of the biblical picture of one flesh. It's nonsensical, by contrast, for anyone to think that the husband is one flesh with his household.

The back-and-forth crossfire in the gender wars can, in part, be traced to our tendency to attempt to solve an uncomfortable mystery rather than honoring the biblical metaphor that describes it. But a careful look at the biblical teaching on marriage may well transcend the gridlock that we're in. Let's take Ephesians 5 as a prime example.

Most evangelicals would probably agree that Ephesians 5 contains the most vivid biblical teaching on marriage. Many, however, argue over ...