There isn’t one, because it doesn’t matter: you’re probably already married.

Simply put, nowhere in the Bible is any form of marriage ceremony required for a marriage to have taken place. Indeed, when you look at the early Biblical patriarchs who lived before the Law of Moses, their marriages are described with verses along the lines of “And then he took her into his tent and lay with her” - no formal ceremony was required. In the Law of Moses when it talks about marriage, it talks about when it is required to occur and how it might be ended, but it doesn’t describe any form of formal ceremony. When Jesus talks about marriage, he mentions “becoming one flesh” (that is, having sex), but he also discusses the new couple leaving their parents’ houses to live together.

As a result, things like “pre-marital sex” don’t really exist; if you’re in a relationship with someone, and you have sex with them, congratulations, you’re married. I say “in a relationship with someone” because men were allowed to hire prostitutes under the Law of Moses (though Paul has forbidden Christians from doing so), and there’s no mention of that resulting in marriage. There’s also one other exception: if you have promised to marry a girl at some point in the future, and then you have sex with her prior to the agreed-upon date or conditions being met (e.g. “I’ll work on your farm for seven years in exchange for marrying your daughter”).

I know that the Catholic Church would disagree with this analysis of Scripture, since they require the formal ceremonies to be held in their churches for them to view marriages as valid, but their views on how “sacraments” work is almost entirely extra-Biblical (though discussion of one of the biggest doctrinal differences between Catholicism and Protestantism is probably off-topic to this question).

This may very well more be a cultural prohibition in the church than a flat out this Bible verse says we should not therefore we should not. I think in Biblical times it would be totally unheard of for Jewish couples to live together pre marriage. This seems to be too recent of a phenomena to have the Bible discuss it.

Another issue that I think worth raising as Christians you should not give in to temptation. Now here I do not just talk about sexual temptation but the temptation to do what is considered good in the eyes of the world and not what is considered good in the eyes of God.

To be honest those who live together pre maritally are usually the same people who have a flagrant disregard for the marital values that the religions of the west are build upon.

Why would want to be part of such a tradition? Even if you can look past all the temptation you will be facing every night you come back from work why would you risk your own path with God in such a manner? It is hard enough to not fall into sin with your girlfriend when she is not living with you. Why risk it?

Also I'm left wondering why if a couple is financially able to afford living together and they seem to be both religious why not just get married? You do not need a large ceremony for your case to be right.

Our age of relativism often cause us to express a kind of naivety to reality by imagining that an intellectual position or argument can resolve any or most situations. We live in a fallen world, which includes our carnal nature even when we become "born again". Ps. 51;5 declares our very conception is sinful. We do not lose our old nature. It has to be kept in subjection by our new or spiritual nature.

I am not inferring that it is impossible for persons to live in a chaste union Christian or not. the understanding that we are Christians placed as light in a fallen world is not a personal matter that is based on how well we can argue or prove our integrity. It is based on making our conduct to the best of our abilities not only satisfying to our consciences, but also to be above public reproach.

Whether we are married or not as two persons of the opposite sex living together, people are naturally inquisitive not firstly about what we practice behind close doors but our relationship to each other. If we are not family the natural tendency of persons is to think of intimate relationship, even if we imagine this negative or judgmental. And even family relations can become questionable according to the present societal trends which sadly are also reality.

Jesus Christ declares even in God's sending of light Jn.3:19* ..man loved darkness rather than light.... We have a responsibilty according to 1 Thess.5:22 Abstain from all appearance of evil. Concerning fornication this is described firstly as self destructive activity as fire itself 1 Cor. 6:18 and Prov. 6:27. It is not to be casually entertained in a context of self control but rather radically avoided. I Cor. 6:18 Flee fornication

Frankly, even if the Bible/Scripture is your guide for both faith and practice, the issue of single Christian men and single Christian women living together under the same roof (or as the IRS used to categorize such folks, POSSLQs--persons of the opposite sex sharing living quarters) is not in the Bible, at least not in the one I read.

Does that mean single Christian men and single Christian women of virtually any stripe are free to live together--chastely, of course--prior to marriage? Not necessarily.

Christians, generally, look to the Bible for guiding principles in how to live their lives, not hard and fast rules which cover each and every contingency in life. Those who attempt to do the latter are in danger of becoming Pharisaical legalists, whereas those who do the former are on safer ground, particularly if they have developed a sensitivity to the nudgings of the Holy Spirit as he brings particular guiding principles to bear on their unique life situations.

When these nudgings occur (and more importantly when we listen to and obey them) we begin to develop some spiritual muscles, which means, in part, we become increasingly aware of and sensitive to not only what is "right" and what is "wrong," but also what is "wise" and what is "foolish," and what is the loving thing to do and the unloving thing to do.

Paul covers this latter category (viz., loving and unloving) quite well in his letter to the Roman Christians, where in chapters 14 and 15 Paul deals with what could be called "principles of conscience" or "grey issues." In those chapters, Paul encourages mature, strong Christians to be willing to give up a behavior they have the personal freedom to engage in, for the sake of other Christians who would stumble if they knew their fellow Christians engaged in that particular behavior, whatever it might be.

Paul sums up the concept in the following way. Do keep in mind, however, that the issues of conscience in his day were 1) food sacrificed to idols, which some Christians had liberty to eat but others did not; and 2) "special days" in the church calendar, which some Christians felt obligated to observe, but which other believers considered strictly "optional."

I know and am convinced in the Lord Jesus that nothing is unclean in itself; but to him who thinks anything to be unclean, to him it is unclean. For if because of food [or a "special" day] your brother is hurt, you are no longer walking according to love. Do not destroy with your food [or with your observance or non-observance of a special day] him for whom Christ died. Therefore do not let what is for you a good thing be spoken of as evil, for the kingdom of God is not [a matter of] eating and drinking [or special days], but righteousness and peace and joy in the Holy Spirit (Romans 15:14-17 NASB Updated).

All the foregoing to say, the primary question a Christian should ask him- or herself is this: How will my behavior affect others either inside or outside the church, whether they are fellow believers or even non-Christ followers, since even the latter are sometimes watching our every move, looking for inconsistency and hypocrisy?

Keep in mind, our consciences alone cannot be our guide, but only consciences informed and sensitized by the principles of God's word. I have observed over my many years of being a Christian, however, that even having a solid foundation in God's word does not keep us--myself included--from rationalizing virtually any behavior we might care to name. That is one reason why Christians need to live in community with other Christians and interact with fellow believers of all different stages of maturity in Christ.

In other words, we need to be accountable to one another and not be "Lone Ranger Christians," indifferent to how our behavior affects others.

In conclusion, perhaps a parable might be helpful regarding the issue of whether or not to live together with another Christian prior to marrying him or her.

In the days when well-to-do people could afford to be chauffeured around in a horse and buggy, they would hire a man (sorry, ladies) to do the "driving" for them. The driver might even become a fulltime employee of the wealthy person.

One day, just such a wealthy man was in need of a driver, so he put an ad in the local newspaper which read simply, "CARRIAGE DRIVER WANTED IMMEDIATELY. MUST MEET CERTAIN QUALIFICATIONS AND PERFORM A TEST RUN IN ORDER TO QUALIFY FOR EMPLOYMENT."

The ad was successful, and it attracted numerous applicants. After vetting each applicant's qualifications and references, the employer had narrowed down the field to just two applicants. He then told the first applicant to prepare for a test run. After giving him directions for the run, he stepped into the carriage and tried to relax.

Well, the first driver took off like a shot and drove the horse as if he were trying to win the Kentucky Derby. When he came to an extreme curve in the road, which had a very steep cliff on one side, he expertly steered the buggy mere inches from the dangerous precipice and arrived home in record time.

The employer then gave the second applicant the same instructions and again got into the cab and tried to relax, which was no mean feat at this point! The driver took off slowly and gently, giving the horse an easy time of it. At the same extreme curve in the road, this driver stayed several feet away from the precipice and arrived home safely, albeit in something less than record time.

The moral of the story: Who do you think got the job?

Selah.

What is the Biblical basis for it being wrong for couples to live together chastely before marriage?

Living together “chastely” may be like trying to diet in a grocery store. The Bible describes two common states;

1 Corinthians 7:9 But if they cannot contain, let them marry: for it is better to marry than to burn.

God designed humans to have passion for each other. He also instituted marriage.

Genesis 2:24 Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.

The idea of living together chastely is more of a fiction that many young people tell their elders today to get them to stop objecting to living together without marriage. So the major Biblical basis would be to not lie.

John 8:44 Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.

Lying to and manipulating parents for ones convenience would seem to constitute a violation of the forth commandment;

Exodus 20:12 Honour thy father and thy mother: that thy days may be long upon the land which the LORD thy God giveth thee.

Even if young people were foolish enough to think that they could live together chastely, they are instructed to get out of the situation that inflames this passion.

2 Timothy 2:22 Flee also youthful lusts: but follow righteousness, faith, charity, peace, with them that call on the Lord out of a pure heart.