God says, “You shall not commit adultery” (Exodus 20:14).
Luther explains, “We should fear and love God so that we lead a sexually pure and decent life in what we say and do, and husband and wife love and honor each other.”
Salvageable adds: In explaining most of the commandments, Luther lists things we should not do as well as things we should do. Only in the first commandment and in this commandment does Luther omit the negatives and describe only the positives. Perhaps he feared that the list of things we should not do regarding marriage and intimacy would become too long to be practical. Perhaps he feared that such a list would give people sinful ideas. Probably, though, Luther wanted to emphasize the positive about a matter that too often is discussed only in negative terms.
As people hunger for food and thirst for water, so most people have an appetite for the intimacy that belongs in marriage. God created that appetite for good reasons, including the mutual support of a man and a woman, and the raising of children in a secure environment. As people can crave food and drink that is not healthy for them, so people can seek to satisfy their desire for intimacy in ways that are impure and indecent. This commandment of God protects marriages. Marriage is important to God. In a perfect world, he created a man and a woman, both in his image, to love and honor each other, to care for the planet and all that it contains and to be helpers or teammates to one another.
The devil and the sinful world hate everything that is good. They seek to damage or destroy the good things God made, twisting those good things into things that are adulterated, indecent, and impure. Whether a person is married or single, that person should respect the marriages of others and not seek to undermine them, whether for personal gain or just out of spite and envy. Jesus said that looking at another person for the purpose of lust is adultery, but the world surrounds us with suggestive images, seeking to inspire lust within us. Lust is sinful, not merely because of this commandment, but also because it treats another person as an object, an It, rather than a person, a Thou. The devil has an additional trick, throwing guilt at a person who has been tempted and has resisted the temptation. Luther had an expression for people who felt guilty about experiencing temptation: “You cannot keep the birds from flying over your head, but you can keep them from building a nest in your hair.” When we encounter temptations to sin and resist them, we should feel thankful and not guilty, for we are partaking in the victory Jesus won over all evil.
Also, Luther may have noted how Bible writers often compare idolatry to adultery. They do this because God compares his people—Israel in the Old Testament and the Church in the New Testament—to his Bride, saying that he loves his people as a husband loves his wife. Any attack on marriage, then, is an attack on love in general and on God’s love in particular. Paul counseled husbands to love their lives as Christ loves the Church; he goes on to paint a picture of Christ purifying the Church by his own sacrifice to make her holy and acceptable. Having been made pure, we want to remain pure. Christ’s forgiveness is available every day to remove the stain of sin from our lives. This redemption changes us, subtracting lust from our hearts, teaching us truly to love, building intimate love within marriages, and causing us to respect also the marriages of others. J.