Lesson 4: But Why Is Sex Outside Of Marriage Wrong?

“Marriage is to be held in honor among all, and the marriage bed is to be undefiled; for fornicators and adulterers God will judge.”

(Hebrews 13:4, NASB95)

One cannot look at Hebrews 13.4 and conclude anything other than sex outside of marriage, whether fornication or adultery, is wrong. This isn’t a Puritan sexual ethic that was warped over time, rather the declaration of God Himself (see Exodus 20.14; Matthew 5.27-28). But why has God declared that sex within marriage is a blessing, but sex outside of marriage will incur His wrath? (Note: I’m indebted to the book “Hooked: New Science on How Casual Sex Is Affecting Our Children” by Joe S. McIlhaney, Jr. MD and Freda McKissic Bush, MD for the statistical and scientific evidence I discuss below).

God’s will is for our good, so sex outside of marriage must not be for our good.

While we should obey the will of God because of the authority He possesses (Matthew 28.18), we should also trust that His commands are for our benefit (Deuteronomy 10.13). So, what is bad about sex outside of marriage? Chances are, two ills come to our minds: sexually transmitted diseases and unwanted pregnancy. And truly, these are problems! Consider the following statistics:

• Each year, 19 million new cases are contracted. Half of these are in people under the age of 25.
• 80% of unwed fathers don’t marry the teen mother of their baby
• 80% of unwed teen mothers eventually receive welfare
• 50% of all single mothers on welfare were teenagers when they had their first baby
• 70% of unwed mothers receive no financial support from the fathers of their children
• Teen mothers receive an average of $67 per month in child support

Rather than placing our trust in God and following His will, society has tried to address these ills via abortion and “safe sex”. One supposed solution, abortion, is evil while the other solution, “safe sex”, is often not effective. Nevertheless, there remains a third problem which society has not begun to address, nor can it. The third problem with sex outside of marriage is that it damages our ability to bond and form life-long attachment to our mate. To understand this, we will have to examine what happens in our brains during sexual activity on a neuro-chemical.

What happens in our brains during sex.

When consensual sexual activity occurs, not just intercourse, a couple of neuro-chemicals are released in our brains. The first, dopamine, is responsible for the pleasure we experience. The second, oxytocin in women and vasopressin in men, is responsible for the bond one feels with his/her partner. The power of these chemicals must not be underestimated! Consider that as soon as a baby is born, he/she is placed against the bare skin of his/her mother. This contact releases these bonding neuro-chemicals, forming an attachment between mother and child. Having this understanding allows us to better understand why sex outside of marriage is wrong in the eyes of God:

1. Neuro-chemicals are values neutral. For instance, your brain will release dopamine when you engage in a number of dangerous behaviors (driving too fast, smoking, drug use, etc.). Dopamine is a strong reward, and since “sex is one of the strongest generators of the dopamine reward. For this reason, young people particularly are vulnerable to falling into a cycle of dopamine reward for unwise sexual behavior – they can get hooked on it.” (Hooked 35) This helps explain why the younger a person is when they first engage in sexual intimacy, the number of voluntary sexual partners they will have increases exponentially (Hooked 65,75).
2. Since neuro-chemicals strengthen the bonds we have with others, there are awful consequences when a relationship ends. “sexually active teen girls were shown to be three times as likely to report that they are depressed all, most of, or a lot of the time as compared to girls who are still abstinent. Sexually active boys are more than twice as likely to report depression as boys who are still abstinent. Sexually active girls are three times as likely as non-sexually active girls to have attempted suicide, while sexually active boys are seven times as likely as non-sexually active boys to have attempted suicide.” (Hooked 78)
3. Since neuro-chemicals strengthen the bonds we have with others, numerous sexual relationships will damage our ability to form lasting bonds. “research indicates that bonding does occur, even when a couple has only engaged in sex a single time… there is evidence that when this sex/bonding/breaking-up cycle is repeated a few or many times – even when the bonding was short-lived – damage is done to the important, built-in ability to develop significant and meaningful connection to other human beings.” (Hooked 55-57).

Marriage is a connected relationship (Genesis 2.23-24), and if sex outside of marriage damages our ability to form the connection of marriage then it cannot be called good! “Marriage is to be held in honor among all, and the marriage bed is to be undefiled; for fornicators and adulterers God will judge.” (Hebrews 13:4) 

Why marriage is so good.

The term “good” has a broad range of meaning. We call something “good” if it pleases us in some way or if something serves its purpose, doing what it is supposed to. In Genesis 1 God calls His creation “good” 6 times (vss. 4, 10, 12, 18, 21, 25) and once called it “very good” (vs. 31). But, significantly, when God describes man in Genesis 2.18, He says it is “not good…” God calls something “good” because 1) it fulfills its purpose and thus 2) it pleases Him. But when God considered man He saw that while man was alone and without a helper comparable to Him, man could not fulfill his purpose. Man’s state was not good, so God created woman to complete man… so that both could be “good”.

The goodness of marriage is emphasized in Genesis 2.23-24, “The 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.” For this reason a man shall leave his father and his mother, and be joined to his wife; and they shall become one flesh.” Marriage is good for three important reasons:

1. Marriage is “good” because it requires real love.
   • Woman was “bone of my bones, and flesh of my flesh”, and as Paul would later emphasize, this is the reason why man should love his wife (Ephesians 5.28-30).
   • This love isn’t limited to an emotional experience, but is an active pursuit of what is good for another (1Corinthians 13.4-7).
   • This kind of love is required of both husband (Ephesians 5.25,28-29) and wife (Titus 2.4).
2. Marriage is “good” because it requires true commitment.
   • Husband and wife become “one flesh” and Jesus would explain this is the reason why divorce should not occur (Matthew 19.4-6).
   • The commitment of marriage is more than the agreement to not divorce, but is a total commitment of one’s thoughts and affections (Matthew 5.27-28).
   • The commitment of marriage is the complete submission to the needs of the other (Ephesians 5.21-33).
3. Marriage is “good” because it prepares us for our relationship with God.
   • God’s relationship with His people is described as a marriage (Ezekiel 16.8-14; Isaiah 54.5; Ephesians 5.22-30; 2Corinthians 11.2).
   • And He is asking us to truly love Him (John 14.15) and to remain committed to Him (Revelation 2.10; Mark 9.23).
   • So, the ultimate “good” of marriage is that it encourages the love and commitment that have to be present in our relationship with God.

So, why is “the marriage bed undefiled”? Because sex helps bond a man and woman together. The pleasure of dopamine means they will desire further intimacy with each other. The release of oxytocin and vasopressin will strengthen the attachment they have. Why is it that “fornicators and adulterers God will judge”? Because sex outside of marriage seeks pleasure without attaching oneself fully to another. Remember, the ultimate reason why marriage is good is because it’s a picture of our relationship with God. God wants a bond with us, the bond that can only truly exist in marriage.