Q. 21. What is meant by the seventh commandment, “You shall not commit adultery”?

We should be pure, decent, and chaste, both within and outside of holy marriage. God forbids all impure thoughts, words, or behaviors, such as lust, immodesty, pornography, fornication, cohabitation, homosexuality, and unlawful divorce.

Marriage was ordained by God as a sign of the mystical union between Christ and his Church, and should be honored by all with love, purity, and devotion. 

Genesis 2:24; Leviticus 18:22; Job 31:1; Proverbs 6:23–35; Malachi 2:15–16; Matthew 5:27–32; 19:4–6; Mark 10:6–9, 11–12; Romans 1:24–27; 1 Corinthians 6:9–10, 18–20; 7:1–5, 36–38; Ephesians 5:3–5; Philippians 4:8; Colossians 3:5; Galatians 5:19–21; 1 Thessalonians 4:3–5; 1 Timothy 1:10; Hebrews 13:4.

  • WSC 71–72
  • Heidelberg Catechism 108–109
  • WCF 24

Pure … chaste. Chastity is the virtue of being pure in conduct and intention, undefiled by any kind of unlawful sexual intercourse.

Decent. Decency is the virtue of being modest and appropriate, free from obscenity, lewdness, or coarseness.

Within … holy marriage. Marriage is the consensual, lifelong union of one man and one woman in a partnership of the whole life (see p. 344, “Holy Marriage”). Sexual immorality disrupts the beautiful harmony of a holy marriage. “No relationship between two men is as close as that between a man and a woman, if they are joined together as they should be. … This love is truly more tyrannical than any tyrant. Other passions may be strong; this passion is not only strong but also imperishable. For deeply implanted in our nature there is a certain desire (eros) that, without our noticing it, knits together these bodies of ours. That is why from the beginning woman came from man, and later man and woman came from man and woman. Do you see the bond and the connection, and how God did not allow any other substance from the outside to come between them?” (John Chrysostom, Homilies on Ephesians 20).

Outside. Celibacy was modeled by the Lord Jesus Christ and the Apostle Paul, and has been held in high honor by the Church throughout history (1 Corinthians 7:6–8; 32–35). Singleness is not an inferior state of life, though it may be more difficult for some to remain pure and holy (1 Corinthians 7:9).

Lust. “Everyone who looks at a woman with lustful intent has already committed adultery with her in his heart” (Matthew 5:28). Adultery of the heart injures the bond of marriage.

Immodesty. God forbids obscene talk, coarse joking, flirtatious behavior, and indecent apparel. We should cover our nakedness, in part to avoid inciting lust. Love constrains us to avoid placing a stumbling block in front of our neighbor.

Pornography. Pornography is a perversion of human sexuality and a cheap substitute for real intimacy. Sexual intimacy within a loving marriage is deeply satisfying and binds us more closely with our spouse in love; pornography is profoundly unsatisfying and leaves us ashamed, empty, and longing for more.

Fornication, cohabitation. All sexual activity outside of marriage is forbidden by God. It is sinful for those who are dating or engaged to live together before marriage and have a sexual relationship. “Let marriage be held in honor among all, and let the marriage bed be undefiled, for God will judge the sexually immoral and adulterous” (Hebrews 13:4).

Homosexuality. Homosexual behavior is consistently condemned by Scripture alongside adultery and other kinds of sexual immorality (Romans 1:26–27; 1 Corinthians 6:9; 1 Timothy 1:10). Same-sex attraction is one of many disordered affections resulting from the fall. A person may be persistently tempted towards romantic or sexual intimacy with the same sex, but this does not justify homosexual lust or behavior.

Unlawful divorce. Marriage is a lifelong covenant (see p. 344, “Holy Marriage”). The only cases specified by Scripture in which divorce may be acceptable are when someone’s spouse commits adultery (Matthew 5:32), or when their spouse is an unbeliever who abandons the marriage (1 Corinthians 7:15). In cases of abuse, a spouse may separate for their safety or the safety of their children. In all cases, wise pastoral counsel should be sought.

  1. If Polyamory, Why Not Polygamy?
  2. More coming soon