But the implicit question it poses is: what is the Christian view of sex outside marriage? For those who are already married, the answer is clear: "You shall not commit adultery" is commandment seven of the Ten (Exodus 14), coming after murder and ahead of stealing. In its social context, where it was assumed all adults were married, and men were the main social agents, it was primarily a command to men not to have sex with another man’s wife. However, in the ‘casuistic’ regulations (dealing with cases, ‘If X happens, you must do Y’) of Deuteronomy 22:22, both parties to adultery are held to be equally responsible. None of these texts specify whether the man involved is married.
The main text in the Old Testament offering regulation of sexual activity is in the ‘epideictic’ passage (not dealing with cases, but in absolutes, "You shall [not]…") in Leviticus 18. Sexual activity is prohibited with close relations, with a women during menstruation, with someone else’s wife, with other men, or with animals. But there is no explicit prohibition of sex before marriage.
The best explanation of this is simply that it wasn’t necessary. In ancient cultures, with no reliable method of contraception and with women dependent on their husbands for financial provision and social standing, sex could not be detached from marriage. The closest we get to a prohibition on sex before marriage is in the (casuistic) command in Deuteronomy 22:28: if a man has sex with an unmarried or unbetrothed woman, then they must marry. There has been much debate about this verse (should a woman be forced to marry the person who raped her?) but, along with other texts, it highlights the assumed context. Sex belongs in marriage; unmarried women and men abstain from sex; and even when they are betrothed (committed to marrying), they do not have sex until after marriage. And this makes sense of the earlier case, if a man accuses his newly-wed wife of not being a virgin (Deuteronomy 22:13–21); if she has had sex already, she is in effect another man’s wife, and the penalty is the same as that for adultery. (Note that the accusation cannot be made lightly; the penalty for false accusation is significant.)
This is the pattern assumed in the narrative of the creation of Eve in Genesis 2:24. The order is clear: "a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh." The old social organisation is disrupted as the man leaves his birth family; the man and his wife form a new social unit ("hold fast" or "cleave" is language used elsewhere of tribes settling in their territory); and they then have sex. This pattern is reflected in the language of the Church of England wedding service: "May the union of their bodies strengthen the union of their hearts and minds." Dr Ian Paul. CT.
Blogger: John 4:16 - 18 is worth a look. Also 1 Corinthians 7, Hebrews 13:4, Ephesians: 5 -5.