First lets get the definitions out of the way.
Main Entry: for·ni·ca·tion
Date: 14th century
: consensual sexual intercourse between two persons not married to each other -- compare ADULTERY
Main Entry: adul·tery
Date: 15th century
: voluntary sexual intercourse between a married man and someone other than his wife or between a married woman and someone other than her husband; also : an act of adultery
Main Entry: cov·e·nant
Date: 14th century
1 : a usually formal, solemn, and binding agreement
2 b : a written agreement or promise usually under seal between two or more parties especially for the performance of some action b : the common-law action to recover damages for breach of such a contract
Now that you understand that fornication is between two persons not married and that adultery is also done with someone that you are not married to. Here are some scriptures that are very clear that these are not good things and are sin and despised by God.
Matthew 15:18-20
But the things that proceed out of the mouth come from the heart, and those defile the man. For out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, slanders. These are the things which defile the man; but to eat with unwashed hands does not defile the man."
Exodus 20:14 & Deuteronomy 5:18
"You shall not commit adultery."
Proverbs 6:32
"The one who commits adultery with a woman is lacking sense; He who would destroy himself does it."
Hosea 4:1,2
"Listen to the word of the LORD, O sons of Israel, For the LORD has a case against the inhabitants of the land, Because there is no faithfulness or kindness Or knowledge of God in the land. There is swearing, deception, murder, stealing and adultery. They employ violence, so that bloodshed follows bloodshed."
Matthew 5:28
"but I say to you that everyone who looks at a woman with lust for her has already committed adultery with her in his heart."
1 Corinthians 7:9
"But if they do not have self-control, let them marry; for it is better to marry than to burn with passion."
We could go on an on with more verses but I think that this is clear enough. Fornication is sin. Fornication is sexual relations with someone outside of marriage. Adultery is sin. Lusting for anyone outside of marriage is sin. There is also the story of Jesus with the woman at the well in John 4.
John 4:17,18 The woman answered and said, "I have no husband." Jesus said to her, "You have correctly said, 'I have no husband'; for you have had five husbands, and the one whom you now have is not your husband; this you have said truly."
Jesus says very clearly here that the person that she is living with is not her husband. She is living with him and that does not constitute a marriage.
As far as marriage goes, the Bible is not very clear or specific on what acts need to be done to be married. However, just as the Bible does not say though shalt not listen to rock music, you can gather by looking at scripture and the character of God that it is not right. Marriage is the same. There are many verses that speak of marriage but do not speak to that acts that made the two married. But again, taking scripture as a whole and the character of God, we can come to some conclusions about marriage.
Weddings are public events
The Bible talks of weddings and how it was public event where people are invited to witness the covenant between the two getting married.
- Matthew 22:1-13 is a parable that Jesus tells of a wedding. People are invited, it is an event with many witnesses.
- John 2:1-12 Jesus is at a wedding because He was invited to it along with many others.
- Ruth 4:10 Ruth is purchased and is taken as the wife as Boaz in with presence of many witnesses.
There are other passages as well but as you can see, weddings we events that people were invited to and were celebrated things. The taking of a wife was something that there were witnesses to. There are verses that talk of weddings being public events where witnesses gather together. What I was not able to find was verses that said that weddings were secret or hidden or that they just happened in peoples heart. There are passages that dont give detail as to what happened but the ones that do, they state a public event and witnesses.
Another way to look at this is that in the Bible marriage was binding. A married man or woman just couldnt walk away from a marriage. They were binded by the covenant that they made when they got married. Here is an example of where one is bond to the covenant of marriage.
Malachi 2:14 Yet you say, 'For what reason?' Because the LORD has been a witness between you and the wife of your youth, against whom you have dealt treacherously, though she is your companion and your wife by covenant.
Here it talks not about people being witness but God. It also says that there is a covenant between a husband and a wife. Going back to the definition of covenant it is a binding agreement. Also Deuteronomy 24:1,3 talks about a certificate of divorce. Why would you need a certificate of it was never a binding agreement in the first place? Matthew 5:21 states that if anyone sends away his wife that they must send them with a certificate of divorce. Again why bother if there was not a binding agreement? Why all the paperwork? Note that it is a piece of paper, a certificate. It is officially dissolving the marriage agreements between two people. If there is a certificate of divorce that makes the dissolving of a marriage official, wouldnt it make sense that there is a certificate or a piece of paper making it official between them in the first place? If you are just living with someone, do you have this certificate? If something were to happen and you walked away, would you have a divorce certificate. No, because you we never married in the first place.
If you add it all up you get that marriage is a binding agreement that is witnessed by others and God that has a paper trail. We also see that in most of the references that it is a public event where people are invited and it is a feast. So living together before marriage and having sex and loving each other with all your heart does not make you married. And since you are not married then what you are doing is fornication and adultery which is sinning against God.
