Sean McDowell | December 15, 2020

Is Sleeping with Someone Outside Marriage Wrong? (A Case without Using the Bible)

Recently a young man asked me if I could make a case for the moral wrongness of premarital sex without using Scripture. I simply said: Premarital sex is wrong, because you shouldn’t lie. He didn't expect me to say that, and I'm guessing that may be true for you too.

A lie involves saying something that is not true. To lie is to knowingly convey a false view of reality. When we properly understand the meaning of sex, and what it communicates between two people, this is what premarital sex does. Let me explain.

Communicating Without Words

We must begin by recognizing that we communicate with our bodies and with our words. As a communications major in college, my professors often told me that we communicate more non-verbally than we do verbally.

Recently I asked a group of high school students to come up with some examples of how we communicate with our bodies. They came up with some culturally bound examples, such a giving someone the middle finger or winking. And they also came up with some cross-cultural examples such as a slap on the face.

We even talked about the meaning of a kiss, and how a kiss on the cheek communicates something different than a kiss on the forehead. While they debated the meaning of various kinds of kisses, they concluded that a French kiss implies romantic intentions and exclusivity by its very nature.

Lying with Our Bodies

In sum, they all agreed that bodily actions carry intrinsic meaning. Thus, they also agreed that it is possible to lie with our bodies. Here is how I put it in Chasing Love:

Suppose a used-car salesman sells you a car while withholding a problem with the transmission, and then shakes your hand. Did he lie with his body? Of course. Imagine smiling and hugging someone you deeply dislike. Are you communicating something you don’t really feel? What about a wink at someone you are not attracted to? Is that a lie? It certainly can be.”

What Sex Means

After my students agreed that we communicate with our bodies, I asked them another question: “What does sex communicate?” After much discussion, they concluded that sex communicates trust, since you make yourself intensely vulnerable with your partner. They agreed that sex communicates exclusivity, since we all recognize that a boyfriend or girlfriend feels cheated on when someone has sex with another person. And they agreed that sex communicates permanence, since sex is a procreative act that produces children who both want and need their parents throughout their lifetimes.

Don’t we all know that sex means these things, even if we choose to act differently? In the 2001 psychological thriller Vanilla Sky, Tom Cruise plays the role of a rich business owner who falls in love with a girl he meets at a party. When his current lover finds out they slept together, she begins stalking him. In one of the more memorable lines from the film, she says, “Don’t you know that when you sleep with someone, your body makes a promise whether you do or not.”

She’s right, we communicate with our bodies. We can speak truth with our bodies. We can tell lies with our bodies. We can even break a promise with them.

Why Premarital Sex Is A Lie

So, why is premarital sex lying? Because the physical act of sex communicates trust, exclusivity, and permanence, and yet these are only matched relationally in marriage when someone has said, “I do.”

To engage in premarital sex is to communicate one thing with your body but fail to match it up with your words. Isn’t that a lie?

If you’re looking for a biblically-based and timely resource on sex, love, and relationships, check out my latest book for students: Chasing Love: Sex, Love, and Relationships in A Confused Culture.

Sean McDowell, Ph.D. is a professor of Christian Apologetics at Biola University, a best-selling author, popular speaker, and part-time high school teacher. Follow him on Twitter: @sean_mcdowell, TikTok, Instagram, and his blog: