Is Sex Outside of Marriage a Sin?

For many, the traditional Christian belief that sex is reserved for marriage between a man and woman is outdated and unrealistic.

What’s more, many see it as judgmental and legalistic. They feel churches should stop focusing so much on sex and just concentrate on showing people Jesus’ love.

To them, in light of everything else going on in the world, sex outside marriage is just no big deal.

There are many arguments people make for why sex outside marriage between a man and woman should no longer be considered sinful.

Here are a few of the most popular:

1. There’s evidence that sex outside of marriage was a common practice, even among Israelites in the Old Testament (see Genesis 38:15-26).
2. Old Testament sexual prohibitions were rooted in concerns about property violation, because the culture saw women as men’s property.
3. The biblical word for “fornication” is porneia. But that refers to sexual promiscuity usually associated with idolatrous religious practice. It wasn’t referring to sexual expressions of committed love.

In general, the reasons given for no longer considering sex outside marriage a sin rely on reasoning that what was considered wrong in the ancient culture of the Bible is no longer considered wrong in our culture.

But is this a reliable way of determining whether or not we should obey God’s commands?

We need to remember that all of God’s commandments flow from his holy nature and eternal purpose.

While it’s true that some of God’s commandments were unique to Israel and therefore no longer binding on us, we need to remember that all of God’s commandments flow from his holy nature and eternal purpose.

Determining whether or not sex outside marriage is sin requires determining how sex and marriage relate to God’s unchanging holiness and eternal will.

Why did God create marriage?

Marriage is obviously not unique to Christianity, but the Christian understanding of marriage is.

Therefore, it’s important that we form our understanding of marriage based on God’s eternal nature and purpose, not cultural sensibilities.

To do this, we must begin with Genesis chapter 2:

²²The Lord God fashioned into a woman the rib which He had taken from the man and brought her to the man.
²³The man said,
  “This is now bone of my bones,
   And flesh of my flesh;
  She shall be called Woman,
  Because she was taken out of Man.”
²⁴For this reason, a man shall leave his father and his mother, and be joined to his wife; and they shall become one flesh.

In our article “Why Did God Create Male and Female?”, we discussed the unique way that marriage allows humanity to reflect God’s nature as Trinity. The language of verse 24 above, however, makes it very clear that God’s purpose was for marriage to form humanity’s most basic social structure.

The relational bond between husband and wife was meant by God to supersede all others, even that between parents and children.

Marriage is designed by God to establish a lifelong bond between a man and woman typified by the term “one flesh”.

Marriage is designed by God to establish a lifelong bond between a man and woman typified by the term “one flesh”.

Obviously the “one flesh” bond of marriage doesn’t mean a husband and wife literally become one person. What it refers to is sometimes described as the “mystical bond” of marriage.

This bond is the unique way that God has designed a husband and wife in marriage to be so tightly joined together that you can’t refer to one without the other.

If one hurts, the other hurts. If one rejoices, the other rejoices. It’s quite simply the deepest and most profound human relationship a person can experience.

The bond of marriage is meant to be the place of safety and security where a man and woman can express and protect this “one flesh” union of relational love.

God’s purpose was also that marriage be established through a covenant made in the public context of community. By this, society as a whole was meant to honour, respect and protect this sacred and fundamental union upon which families and societies could be secured.

What is sex for?

Besides the obvious functions of physical pleasure and making babies, God’s most foundational purpose for the act of having sex is as the means of establishing the “one flesh” union of marriage (see Genesis 2:24).

God’s most foundational purpose for the act of having sex is as the means of establishing the “one flesh” union of marriage

It’s not that having sex makes two people married, but it does produce a “oneness” or uniting between them that God intends for marriages. Lewis Smedes, in his book Sex for Christians gives one of the best explanations:

“It does not matter what two people [having sex] have in mind…The reality of the act, unfelt and unnoticed by them, is this: It unites them – body and soul – to each other. It unites them in that strange, impossible to pinpoint sense of ‘one flesh’.”¹

Simply put, since God’s purpose for marriage is the exclusive, life-long bonding of a husband and wife, God designed sex as the “glue” which establishes and keeps that bond healthy and strong.

Misusing sex for any other purpose violates God’s intended purpose for it.

Conclusion to sex outside marriage

Contrary to popular opinion, the biblical Christian teaching that restricts sexual expression to heterosexual marriage is not a hold-over from some prudish cultural ghetto of the past.

It’s based on the timeless purpose of God the Creator graciously giving to humanity the joy and honour of bearing his image.

It’s based on the timeless purpose of God the Creator to graciously give to humanity the joy and honour of bearing his image.

Ignoring biblical boundaries for sex only serves to distort this good gift from God. And as the apostle Paul warns, we bear the consequences within our very bodies when we do (1 Corinthians 6:18).

It might be possible to avoid the obvious dangers of sexually transmitted diseases (STDs) or unwanted pregnancy. But it’s impossible to escape the inner emotional scarring, relational tensions, and decreased capacity for intimacy that result from misusing God’s life-uniting gift of sex outside the safety of the life-uniting bond of marriage.

Footnotes

¹ Lewis Smedes, Sex for Christians, rev. ed. [Grand Rapids, MI: Eerdmans, 1994], pp. 109-10.