The answer to this question depends somewhat on what is meant by “living together.” If it means having sexual relations, it is definitely wrong. Premarital sex is repeatedly condemned in Scripture, along with all other forms of sexual immorality (Acts 15:20; Romans 1:29; 1 Corinthians 5:1; 6:13, 18; 7:2; 10:8; 2 Corinthians 12:21; Galatians 5:19; Ephesians 5:3; Colossians 3:5; 1 Thessalonians 4:3; Jude 7). The Bible promotes complete abstinence outside of (and before) marriage. Sex before marriage is just as wrong as adultery and other forms of sexual immorality, because they all involve having sex with someone you are not married to.

If “living together” means living in the same house, that is perhaps a different issue. Ultimately, there is nothing wrong with a man and a woman living in the same house—if there is nothing immoral taking place. However, the problem arises in that there is still the appearance of immorality (1 Thessalonians 5:22; Ephesians 5:3), and it could be a tremendous temptation for immorality.

The Bible tells us to flee immorality, not expose ourselves to constant temptations to immorality (1 Corinthians 6:18). Then there is the problem of appearances.
A couple who is living together is assumed to be sleeping together—that is just the nature of things. Even though living in the same house is not sinful in and of itself, the appearance of sin is there. The Bible tells us to avoid the appearance of evil (1 Thessalonians 5:22; Ephesians 5:3), to flee from immorality, and not to cause anyone to stumble or be offended. As a result, it is not honoring to God for a man and a woman to live together outside of marriage.

What does God require in order to consider a marriage to be valid, so that having sex won't be a sin? Do you have to have a public ceremony in the church building? Do you have to register your marriage with the government at a registry? Is traditional marriage considered valid in God's eyes. Because marriage existed long before all these things. So what is the essential element that causes God to give you a green card for sex?

Because in Genesis, it seems that once a woman moved into a man's house and he started calling her his wife, then she was his wife. Simple. From this perspective, the "sin" of cohabitation before marriage seems like something silly that we created by making marriage so complicated.

Seun:
What does God require in order to consider a marriage to be valid, so that having sex won't be a sin? Do you have to have a public ceremony in the church building? Do you have to register your marriage with the government at a registry? Is traditional marriage considered valid in God's eyes. Because marriage existed long before all these things. So what is the essential element that causes God to give you a green card for sex?

Because in Genesis, it seems that once a woman moved into a man's house and he started calling her his wife, then she was his wife. Simple. From this perspective, the "sin" of cohabitation before marriage seems like something silly that we created by making marriage so complicated.

A reading from the Book of Genesis 24:48-51, 58-67
The servant of Abraham said to Laban:
“I bowed down in worship to the Lord,
blessing the Lord, the God of my master Abraham,
who had led me on the right road
to obtain the daughter of my master’s kinsman for his son.
If, therefore, you have in mind to show true loyalty to my master,
let me know;
but if not, let me know that, too.
I can then proceed accordingly.”
Laban and his household said in reply:
“This thing comes from the Lord;
we can say nothing to you either for or against it.
Here is Rebekah, ready for you;
take her with you,
that she may become the wife of your master’s son,
as the Lord has said.”
So they called Rebekah and asked her,
“Do you wish to go with this man?”
She answered, “I do.”
At this they allowed their sister Rebekah and her nurse to take leave,
along with Abraham’s servant and his men.
Invoking a blessing on Rebekah, they said:
“Sister, may you grow
into thousands of myriads;
And may your descendants gain possession
of the gates of their enemies!”
Then Rebekah and her maids started out;
they mounted their camels and followed the man.
so the servant took Rebekah and went on his way.
Meanwhile Isaac had gone from Beer-lahai-roi
and was living in the region of the Negeb.
One day toward evening he went out . . . in the field,
and as he looked around, he noticed that camels were approaching.
Rebekah, too, was looking about, and when she saw him,
she alighted from her camel and asked the servant,
“Who is the man out there, walking through the fields toward us?”
“That is my master,” replied the servant.
Then she covered herself with her veil.
The servant recounted to Isaac all the things he had done.
Then Isaac took Rebekah into his tent;
he married her, and thus she became his wife.
In his love for her Isaac found solace
after the death of his mother Sarah.


that is the biblical procedure.

zyzxx:
A reading from the Book of Genesis 24:48-51, 58-67

that is the biblical procedure.

Did Adam Abraham Moses and others follow that procedure?

Seun:
What does God require in order to consider a marriage to be valid, so that having sex won't be a sin? Do you have to have a public ceremony in the church building? Do you have to register your marriage with the government at a registry? Is traditional marriage considered valid in God's eyes. Because marriage existed long before all these things. So what is the essential element that causes God to give you a green card for sex?

Because in Genesis, it seems that once a woman moved into a man's house and he started calling her his wife, then she was his wife. Simple. From this perspective, the "sin" of cohabitation before marriage seems like something silly that we created by making marriage so complicated.

I think you got it wrong.

(1) In the case of Adam and Eve

The book of Genesis made us to know that God made Eve from Adam's rib and later brought her to Adam and officially handed Eve over to Adam as his wife.
It is this official hand over that made the marriage a legal union. Without official hand over from the bride's family, the marriage is illegal
[Genesis 2:22] Then the LORD God made a woman from the rib, and he brought her to the man.

(2) In the case of Jacob having Rachel and Leah as his wives.

Jacob worked for Laban for seven years as a bride prize to have one of his daughter Rachel as his wife but Laban gave him Leah. Because of the love Jacob have for Rachel, he has no other option than to work for another seven years making it 14years as a bride prize just to have his heart desire Leah as his wife. Jacob didn't just take Rachel and make her his wife because he loves her and want to live her. But Jacob has to go through process for the marriage to be legal. Without the necessary requirements which is the bride prize and official hand over, the marriage is illegal.
[Genesis 29:18] Since Jacob was in love with Rachel, he told her father, “I’ll work for you for seven years if you’ll give me Rachel, your younger daughter, as my wife.”

(3) *Customary bride prize*

God gave this instructions to the people of Israel about having sex with a virgin who is not engaged. What make her a virgin is not having any sexual relationship with any man. If you have sex with her you must marry her.
[Exodus 22:16-17] “If a man seduces a virgin who is not engaged to anyone and has sex with her, he must pay the customary bride price and marry her. 17 But if her father refuses to let him marry her, the man must still pay him an amount equal to the bride price of a virgin.

LoJ:

Did Adam Abraham Moses and others follow that procedure?

For Moses, Yes!
Moses follow the procedure because the wife Zipporah was officially handed over to Moses by her father. Genesis 2:21 Moses accepted the invitation, and he settled there with him. In time, Reuel gave Moses his daughter Zipporah to be his wife.

For Abraham, Bible did not give the detail of how he married Sarah. But through his son Isaac own you will know that he followed the procedure.

...

I dont think there is anythng wrong with it if you av done your traditional rights by paying her dowry, even in d bible if u read bout isaac nd Jacob wedding na dowry dem talk of nd it can cum in any form that both the future groom nd d father of the bride agree on.
coz every other thing no mata, even God recognize tradition wedding more than white nd court weddings.

okekefabi:


For Moses, Yes!
Moses follow the procedure because the wife Zipporah was officially handed over to Moses by her father. Genesis 2:21 Moses accepted the invitation, and he settled there with him. In time, Reuel gave Moses his daughter Zipporah to be his wife.

For Abraham, Bible did not give the detail of how he married Sarah. But through his son Isaac own you will know that he followed the procedure.

What about Adam?

And what about the other wives of Moses?

And Noah? Enoch? Lot? And Cain? And Seth?

Where is it written that should be the procedure?

A couple who is living together is assumed to be sleeping together
Sure there is nothing wrong with intending couples to stay together and in fact have sexually experience. In this age, you wouldn't want to sign any player without trial.
The world is more exposed than it used to be. I know the Bible was inspired by human experience from long ago but human experience is subject to changes in relation to population.

Seun:
What does God require in order to consider a marriage to be valid, so that having sex won't be a sin? Do you have to have a public ceremony in the church building? Do you have to register your marriage with the government at a registry? Is traditional marriage considered valid in God's eyes. Because marriage existed long before all these things. So what is the essential element that causes God to give you a green card for sex?

Because in Genesis, it seems that once a woman moved into a man's house and he started calling her his wife, then she was his wife. Simple. From this perspective, the "sin" of cohabitation before marriage seems like something silly that we created by making marriage so complicated.

Well I don't know much about it from the Christian perpestive.
But I can tell you from the Muslim perpestive.
All you need is.
Full consent of the husband and wife to be.
The presence of two witnesses apart from the imam.
Their guardian’s consent is essential for the validity of marriage.
You can read more about it if you are interested.