“Thou shalt not commit adultery.” (Exodus 20:14)
This commandment’s obvious application is for marital fidelity. God created one man and one woman for that man (Genesis 1:26; 2:18; 1 Corinthians 11:9).
Adam recognized the sanctity of marriage (Genesis 2:23-25). Christ verified and reaffirmed this fidelity (Matthew 5:27; 19:4-6). Adultery “murders” a marriage and was punished with the death penalty (Leviticus 20:10).
The Bible also gives several parallel restrictions. Pre-marital sex is forbidden (Deuteronomy 22:20-21; 1 Corinthians 6:13-18), as is the practice of prostitution (Leviticus 19:29). The perversion of homosexuality is forbidden (Deuteronomy 23:17-18), as was the practice of religious sexual rites (Hosea 4:12-14).
The purpose of these social restrictions in the Mosaic Law is to set a clear and visible distinction between God’s people and the rest of the nations. God abhorred such behavior (Leviticus 20:23) because these sins defiled the land (Leviticus 18:24-28). Perhaps even more damning than the physical sins was the false worship of other gods (Jeremiah 3:20).
The Lord Jesus clearly equated lust and adultery (Matthew 5:28), noting that the heart is the source of all evil actions (Matthew 15:19). In fact, in the New Testament, any worldly association is whoredom and such friendship is enmity with God (James 4:4).
Unfortunately, we are surrounded by an overt promotion of such behavior, enticing all to engage freely. It is distributed to us through books, movies, TV, Internet, music, fashion, and associations. Surely, it is clear that the Christian must conform to biblical standards, not the world’s tolerance or permission (1 John 2:15-17). HMM III