It seems to be a very difficult subject for people to understand in the context of truth. There is only one truth of a subject and we find that the final word on that truth is the word of God. Everyone has an opinion and everyone is entitled to there opinion. But God is the author of truth and we must stay with the one with whom is no variableness, neither shadow of turning about him. For man can be bought off, deceived and manipulated by others, But God is not a man that he should lie, neither the Son of Man that he should repent. (NUM.23:19) God is the final say-so on all matters concerning man-kind. If we will dare listen to him, [ 2 Timothy 3:16] All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:] he will lead us to Holiness and Righteousness through the word of his Son Jesus Christ and to Eternal life with Him. Amen!
Marriage was instituted in the Garden of Eden. Genesis 2:21-25 And the LORD God caused a deep sleep to fall upon Adam, and he slept: and he took one of his ribs, and closed up the flesh instead thereof; 22 And the rib, which the LORD God had taken from man, made he a woman, and brought her unto the man. 23 And Adam said, This is now bone of my bones, and flesh of my flesh: she shall be called Woman, because she was taken out of Man. 24 Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be [one flesh]. And they were both naked, the man and his wife, and were not ashamed. The word cleave means: cling or adhere, abide fast, cleave (fast together) be joined (together); to stick to.
This was also stated by Jesus when the Pharisees also came unto him, tempting him, and saying unto him “Is it lawful for a man to put away his wife for every cause“?
Then he quotes the scriptures of Gen.2:21-25. His first statement was “Have ye not read“? [ Our answers are all found in the Word of God if we will just read and believe] that He (God) which made them at the beginning made them Male and Female, wherefore they are no more twain (two people) but one flesh”. But He added his word to the Scriptures and said “What therefore God hath joined together, Let not man put asunder. Then they said, Why did Moses then command to give a writing of Divorcement, and to put her away? Jesus said “Moses because of the hardness of your hearts [ hard-heartedness: destitute of spiritual perception: hardness of heart] suffered you to put away your wives: But from the beginning it was not so. Then the Word of god made flesh said “ And I say unto you, Whosoever shall put away his wife, except it be for Fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery”
The Apostle Paul, in writing to the Romans said in Romans 7:2,3 For the woman which hath an husband is bound by the law to her husband so long as he liveth; but if the husband be dead, she is loosed from the law of her husband. 3 So then if, while her husband liveth, she be married to another man, she shall be called an adulteress: but if her husband be dead, she is free from that law; so that she is no adulteress, though she be married to another man.
That Law is Gods Word,