“Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge” (Hebrews 13:4).
All adultery is fornication, but not all fornication is adultery.
Much confusion can arise over the similarities and differences between the Bible terms “fornication” (pornos) and “adultery” (moichos).
Pornos (from which the first half of the compound word “pornography” comes) is a broad term; it is used in reference to all illicit sexual expression. Under this “umbrella” term would be premarital sex, perverse (I.e., homosexual) sex, bestiality, polygamy, and adultery.
Moichos is a specific sexual sin. It refers to illicit sex of a married person with someone other than their mate. It can also be used to refer to a legal union of a man and a woman who do not have God’s permission to be married. When Herod Antipas married Herodias, his brother Philip’s rightful wife, he was legally married in the eyes of the Roman government, yet before God it was not lawful (Mark 6:18). Their marriage was an adulterous one.
Whenever a man divorces his wife except for fornication and marries another, he has formed an adulterous union with the second woman. In addition, whoever marries his first (I.e., lawful) wife forms an adulterous union with her (Matthew 19:9). The exact moral mess occurs if it is the woman who initiates the divorce (Mark 10:12).
The severity of God’s punishment of fornicators and adulterers (1 Corinthians 6:9-10; Galatians 5:19-21) emphasizes the high esteem and honor all should have for the divine institution called marriage.
