Living together before marriage is becoming increasingly common, even among Christian couples and for a number of reasons. Before making a lifelong commitment, many couples want a “trial period” to feel out how they both live, and know if taking the relationship to the next level makes sense. Many Christians are adopting the beliefs and practices of the world, and this can be problematic for a number of reasons.
The Bible makes no clear claim that living together before or outside of marriage is living in sin. Given this, many Christians believe that living together before marriage is not living in sin. While there is truth concerning there being no clear claim against it, one of the reasons why an answer to this question isn’t explicitly stated in the Bible is because two unmarried people living together before marriage who planned on being husband and wife was rare, particularly among Jews and Christians.
It is also important that we put “living together” in context. Living together including being in the same space using a husband and wife model, including sexual relations without being married. This is not the same as a man and woman living together in the same space without sexual relations. There is nothing wrong with a man and a woman living together as long as there is nothing immoral taking place. However, this too can be problematic if and when desire and temptation arise. The Bible tells us “But sexual immorality and all impurity or covetousness must not even be named among you, as is proper among saints” (Ephesians 5:3 ESV). As Christians, we are taught that it is important to break away from not immorality, and the temptation that comes with it. The Bible says “Flee from sexual immorality. Every other sin a person commits is outside the body, but the sexually immoral person sins against his own body” (1 Corinthians 6:18 ESV). When we participate in any sexual relations outside of marriage, which includes premarital sex, it is a form of fornication which the Bible defines as sexual sin.
Another issue with Christians living together before marriage has to do with commitment. Marriage is an up-front commitment. In the book of Genesis we are told that a man leaves his father and mother and is united to his wife, and they become one flesh (Genesis 2:24). The Book of Mark also touches on this concept of a man and woman coming together as husband and wife as one flesh. “And the two will become one flesh. So they are no longer two but one flesh (Mark 10:8 ESV). When you are living together and unmarried, there is not the same up-front commitment that you would have with marriage. If a man and a woman aren’t able to share their life together as one flesh in a relationship that is honorable to God, there is not a foundation of trust, and while many will argue that you don’t need a document to define your commitment to someone, thinking that you can be committed to someone without a public profession of marriage is unrealistic.
Glenn Stanton, author of “The Rings Makes All the Difference” believes cohabitation, an arrangement where two people who are married are living together without being married, puts men in the driver’s seat and women at risk, with little leverage in the relationship. In this situation, the man gets what they want in terms of sex and companionship without giving what they fear, and that is commitment. While this take may be a bit broad, it does touch on an important truth. Men long for companionship and a sexual partner and will commit to a marriage when they are ready or desire a particular woman. Women often find themselves with little leverage when they are just living with a man because they are giving themselves without the commitment they would have in marriage. A woman may lose the man she’s living with if he has no interest in commitment.
As Christians, we also have to think about what marriage represents. We can take a look at Ephesians 5:
"Follow God’s example, therefore, as dearly loved children and walk in the way of love, just as Christ loved us and gave himself up for us as a fragrant offering and sacrifice to God. But among you there must not be even a hint of sexual immorality, or of any kind of impurity, or of greed, because these are improper for God’s holy people. Nor should there be obscenity, foolish talk or coarse joking, which are out of place, but rather thanksgiving. For of this you can be sure: No immoral, impure or greedy person—such a person is an idolater—has any inheritance in the kingdom of Christ and of God. Let no one deceive you with empty words, for because of such things God’s wrath comes on those who are disobedient. Therefore do not be partners with them. For you were once darkness, but now you are light in the Lord. Live as children of light (for the fruit of the light consists in all goodness, righteousness and truth) and find out what pleases the Lord. Have nothing to do with the fruitless deeds of darkness, but rather expose them. It is shameful even to mention what the disobedient do in secret. But everything exposed by the light becomes visible—and everything that is illuminated becomes a light. This is why it is said: “Wake up, sleeper, rise from the dead, and Christ will shine on you.”