Marriage began in the mind of God.

God created man; "In the likeness of God MADE He Him, MALE and FEMALE created He them…. And called their name Adam in the Day they were created" Genesis 5;1,2

God took the female part from Adam's side and built another being. On presenting this to Adam he said "This is now bone of my bones, and flesh of my flesh; this shall be called woman, BECAUSE this was taken out of man. THEREFORE, shall a man leave his father and his mother and shall cleave unto his woman: and they shall be one flesh" Genesis 2 21-24. Newberry

Since that day of separation there is a physical urge in the bodies of male and female to be rejoined to the other part.

Marriage is the reversal of this separation. The physical union moreover, is not a mere legal agreement, but an actual oneness of the flesh, in which each is merged in the other, according to the scriptures.

Jesus said in Mark 10: 6-10,

6 But from the beginning of the creation God made them male and female.
7 For this cause shall a man leave his father and mother, and cleave to his wife;
8 And they twain shall be one flesh: so then they are no more twain, but one flesh.
9 What therefore God hath joined together, let not man put asunder.
10 And in the house his disciples asked him again of the same matter

From the beginning of creation God makes them male and female (that is the sexual function) ON THIS ACCOUNT (therefore) man will is destined to leave his parents and will be joined to a woman, and the two will be as ONE FLESH, so that they are no longer two (parts) but one flesh. What God, for ordained for man or YOKES together, let no human separate.

Paul's instructions concerning marriage is written in the Greek writing for this present economy 1 Corinthians 7:1-17.

1 Now concerning the things whereof ye wrote unto me: It is good for a man not to touch a woman.
2 Nevertheless, to avoid fornication, let every man have his own wife, and let every woman have her own husband.
3 Let the husband render unto the wife due benevolence: and likewise also the wife unto the husband.
4 The wife hath not power of her own body, but the husband: and likewise also the husband hath not power of his own body, but the wife.
5 Defraud ye not one the other, except it be with consent for a time, that ye may give yourselves to fasting and prayer; and come together again, that Satan tempt you not for your incontinency.
6 But I speak this by permission, and not of commandment.
7 For I would that all men were even as I myself. But every man hath his proper gift of God, one after this manner, and another after that.
8 I say therefore to the unmarried and widows, It is good for them if they abide even as I.
9 But if they cannot contain, let them marry: for it is better to marry than to burn.
10 And unto the married I command, yet not I, but the Lord, Let not the wife depart from her husband:
11 But and if she depart, let her remain unmarried, or be reconciled to her husband: and let not the husband put away his wife.
12 But to the rest speak I, not the Lord: If any brother hath a wife that believeth not, and she be pleased to dwell with him, let him not put her away.
13 And the woman which hath an husband that believeth not, and if he be pleased to dwell with her, let her not leave him.
14 For the unbelieving husband is sanctified by the wife, and the unbelieving wife is sanctified by the husband: else were your children unclean; but now are they holy.
15 But if the unbelieving depart, let him depart. A brother or a sister is not under bondage in such cases: but God hath called us to peace.
16 For what knowest thou, O wife, whether thou shalt save thy husband? or how knowest thou, O man, whether thou shalt save thy wife?
17 But as God hath distributed to every man, as the Lord hath called every one, so let him walk. And so ordain I in all churches.

Also we read in Ephesians 5:28 ". . . he that loveth his own woman is loving himself" A wife and her husband are one flesh., the WIFE dies with the HUSBAND, but the WOMAN remains. Romans 7:1-3 and 1 Corinthians 11: 7-12. We should seek the help of God when choosing a partner, who can steer us body, soul and spirit to a lasting union.

Adam chose to follow his woman who was deceived. 1 Timothy 2:14 . As a result of this both were expelled from God's presence in the Garden of Eden, and because of the flaming sword (which is the Word of God. Eph 6:17) they could not return. Genesis 3:24

Since that day there is in the soul of man a spiritual urge to be reunited with his Creator. God himself has been visiting and desiring lost mankind to return unto himself. Psalm 8:4. In this dispensation of grace He has provided a legal way. John 3:16. and ch.14:6.

The second Adam is the Lord Jesus Christ who is the Word of God. John 1;1, and 1:14. "The first man (Adam) was out of the earth, earthy: the second man (Christ,) is the Lord out of Heaven. 1 Cor 15:47.

Through God's second Adam ,Christ, we can be united once again, spiritually to our creator, through His word.
The Lord Jesus Christ's desire is "..concerning THOSE who are believing INTO Me.. that they may ALL be ONE, according as thou Father, art IN me, and I, IN thee, that they (the Ecclesia) also may be IN US." John 17:20,21.

When mankind has accepted, by faith God's way back to himself and being part of the Ecclesia, then WE can say "for we are members of His body, of His flesh and of His bones" .Ephesians 5:30
At present the Ecclesia is a virgin espoused, "For I am jealous over you, with a jealousy of God, for I, Paul, betroth you (believers) to one MAN, to present a pure virgin to CHRIST ". 2 Corinthians 11:1-3.

The Spiritual marriage is not far away, so we should seek to, "die to the Law, through the body of Christ for you to become ANOTHER'S, who is aroused from the dead.." Romans 7:1-6

In the near future, the Bridegroom will appear in the air to collect His Ecclesia, to be His wife. 1 Thess. 4:15-18