Charles Ellicott Commentary Hebrews 13:4

"[Let] marriage [be] had in honor among all, and [let] the bed [be] undefiled: for fornicators and adulterers God will judge." — Hebrews 13:4 (ASV)

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 (see note on Acts 15:20) and the prevalence of divorce among Jews (Matthew 5:32) explain the sudden introduction of such warnings: of these sinners the all-seeing God will be the judge. (Compare to 1 Thessalonians 4:6.)