Hebrews 13:4 - Ellicott's Commentary On The Whole Bible

Marriage is honourable in all. — Rather, Let marriage be held in honour among all, and let the bed be undefiled; for fornicators and adulterers God will judge. The precept is directed against impurity (Hebrews 12:16), and also against the false asceticism of men “forbidding to marry” (1 Timothy 4:3). The laxity of morals among Gentiles (Note on Acts 15:20) and the prevalence of divorce amongst Jews (Matthew 5:32) explain the sudden introduction of such warnings: of these sinners the all-seeing God will be the judge. (Comp. 1 Thessalonians 4:6.)