What Does it Mean to Be One Flesh?

When God determined that it was not good for man to be alone, He had Adam fall into a deep sleep and took from his flesh a rib, out of which he made the woman Eve (Genesis 2:22). After the meeting of husband and wife, God's command was for them to be fruitful and multiply the earth. They were made of the same substance; Adam from the ground and Eve from Adam. Both had the Spirit of God breathed in them, and both were made in His image. Though they were two separate people, they were one flesh.

To be 'one flesh' has natural and spiritual meanings.

The natural meaning alludes to the physical oneness of man and wife, which leads to procreation. This oneness in flesh in marriage, is biblically referred to as a "great mystery."

The often-cited biblical allusion to spiritual oneness of flesh refers to the fellowship that the Church enjoys with Christ in holiness.

Physical Oneness 

Physical oneness of flesh refers to the soulish and sexual intimacy between a man and woman, normatively under the covenant of marriage. While many people on earth become one flesh in nonChristian marriages, and technically many join together outside the marriage covenant, this article focuses on the union of Christian married couples while warning against oneness outside of Christ-centered covenant.

Under the Covenant of Marriage

Ephesians 5:31 describes the oneness of a married couple in which "a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh." This verse was a quotation of Jesus' words in Matthew 19:4-6, where He also added that "what God has joined together, let no man put asunder." Literally, the joining of a husband and wife represents the start of something new on the earth - different from that of unions in previous generations and a new canvas for God to use.

From the beginning, God's plan for physical oneness would lead to blessing; Edenic man had the mandate to "fill the earth, and subdue it, having dominion…over every living thing" (Genesis 1:28). Out of the physical oneness of a husband and wife comes the blessing of the Lord, and the exercise of God granted power that, although lost to the kingdom of darkness at the fall, can be redeemed through Christ.

Warning Against Sex Outside of Covenant

Outside of Christ, however, the oneness of flesh is dangerous and subject to the consequences of sin. The Bible warns against sexual sin–the act of becoming physically one with someone outside of the covenant union of marriage. 1 Corinthians 6:16 says, "Do you not know that he who joins himself to a harlot has become one with her?" Also, verse 18 declares that sexual sin is a sin against one's own body, making it different from other sins.

The reality is that oneness of flesh through sexual intercourse was never designed to be a casual act outside of God's purpose and plans. Hebrews 13:4 says, "marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge." Sex should always honor God the creator, as our lives and futures belong to Him.

Oneness in Christ as the Church

"Husbands, love your wives, just as Christ also loved the church and gave Himself for her, that He might sanctify and cleanse her with the washing of water by the word, that He might present her to Himself a glorious church, not having spot or wrinkle or any such thing, but that she should be holy and without blemish." Ephesians 5:25

'One flesh' as it concerns the corporeality of the body of Christ refers to the covenant; blood purchased union between Christ and the Church.

Throughout Scripture, the Church is referred to as the "Bride of Christ," and according to Ephesians 5:25, the bride is redeemed, sanctified, cleansed, and prepared by Christ to be perfect in holiness. The "Bride" is a corporate body of believers with many members. 1 Corinthians chapter 12 highlights the diversity and interdependence of all the members, yet that all are one in Christ, "baptized in the same Spirit."

The nature of this union between Christ and the Church should be reflected in marriage on earth, as Ephesians 5:25 instructs husbands to love their wives as Christ loved the Church. An additional admonition is for wives to respect and submit to their husbands.

Even the very concept of getting married reflects our covenant union with Christ. Before we were one with Christ, we were, in a sense, single, uncommitted, or even betrothed to a lesser entity or with perhaps an inferior covenant. When we were born again into the family of God, our old person died, and a new life began being joined to Christ. Being one flesh in a marriage requires the similar death of single life patterns for the sake of union. That "old" person outside of covenant must stay dead in a marriage–and life as a Christian–so that we can live unto Christ.

Fellowship and Fruitfulness 

"If you abide in Me, and My words abide in you, you will ask what you desire, and it shall be done for you. By this My Father is glorified, that you bear much fruit; so you will be My disciples." John 15-7-8

When we enjoy fellowship with Christ as the bride of Christ, we produce much fruit for His kingdom, just as a marriage would yield physical offspring as a result of oneness. Our fruitfulness individually and collectively as the Church is proof of our fellowship with Christ. In John 15:7, Jesus instructs His disciples about this principle. The act of abiding in Christ compels us to bring forth good works naturally and give God great glory for the world to see, which, in turn, makes us fruitful in fulfilling the Great Commission.

Perpetual Connection to the Head of Christ

Whether physical or spiritual in nature, the union which produces one flesh must have Christ as its head. This is akin to abiding. Colossians 2:19 indicates that perpetual attachment to Christ the head enables the entire body to grow by God.

The head, which represents the mind, will, and intellect, is that of Christ Himself. It informs and establishes the thoughts and the direction of the body. Being 'one flesh' means being of one mind, for there should only be one head and not two. God is not double-minded, and nor is His true Church. To be truly fruitful for God, one must take on the mind of Christ. Two under the covenant of marriage must also do this in order to be on one accord.

Love, the Bond of Perfection

"And over all these virtues put on love, which binds them all together in perfect unity." Colossians 3:14

One aspect of being 'one flesh' in Christ is the bond of love, wherein everything in the body is held together by unconditional, Christian love. Colossians 3:14 indicates that the currency of unity among believers is love, which mandates forgiveness and righteous dealings with each other. This is also important for an earth realm marriage. Verse 13 says, "Make allowance for one another's faults and forgive anyone who offends you. Remember, the Lord forgave you, so you must forgive others." Ultimately, being one flesh requires the bond of love to maintain its integrity of stature and harmony in function. Forgiveness and bearing the fruit of the Spirit are essential in this respect.

The Reign of Peace

Colossians 3:14 "Let the peace of Christ rule in your hearts, since as members of one body you were called to peace."

According to Scripture, the reign of peace is a calling of the body of Christ. It also happens to be a fruit of the Spirit, which can only be produced through constant communion and fellowship with Jesus. To be one flesh means that peace has reigning authority over the entire body. The absence of peace, or chaos, would suggest malady and turmoil within the body, which is also identified as sickness, ultimately leading to impairment or death. In the body of Christ or the oneness of flesh between a husband and wife, peace is imperative, but it is also a natural fruit of those abiding in Christ.

Resistance to Division 

One mechanism of the human body is its ability to resist disease with its immune system. If a union is truly one flesh, there will be a natural resistance to division; The more significant the fellowship and unity, both of which can only be achieved as we are abiding in Christ, the stronger the response. When a godly marriage or a fellowship of believers is threatened with division, an expected response would be resistance through prayer, fellowship, sacrificial love, and giving.

Oneness in union was never supposed to be overcome by such division. Divorce, in marriage, for example, was never part of God's plan. In Mark 10, Jesus pointed out to the Pharisees that Moses permitted divorce instead of man's hardness of heart, but that it was also never meant to be. He says in verses 8 and 9, "So they are no longer two but one flesh. What therefore God has joined together, let not man separate."

Sameness in Kind

Being one flesh conveys the importance of being equally yoked, giving us a mandate to open our hearts and minds only to that which is of Christ, those things which are the same in kind.

Even the order of creation advocates for this. In Genesis 1, God creates a diversity of living things according to their same "kind" (Genesis 1:24). Biological science confirms that interspecies offspring are not viable.

1 Corinthians 15:39 even declares that "Not all flesh is the same," using diversity in creation as a metaphor for the inviability between carnality and Spirit. The soul of flesh and the quickened Spirit in Christ are not the same kind and cannot enjoy fellowship. One must die for the other to live. Just as different species cannot procreate, the works of the flesh and the works of the Spirit are not viable together.

Moreover, people living for Christ should avoid worldly soulish bonds which take the rightful place of Christ and His body. 2 Corinthians 6:14 rhetorically poses the question, "For what fellowship has light with darkness?" Amos 3:3 says, "Can two walk together if they are not agreed?" True fellowship indicates 'oneness,' and as Christians, we must walk, maintaining fellowship with Christ first and foremost.

Becoming one flesh is indeed a great mystery. When a man and a woman come together in marriage, they create something new and unique. When a person surrenders their life to Christ, they become a new person. In the physical, oneness is evidenced by reproductive fruitfulness. In the Spirit, oneness with Christ is evidenced by bearing the fruit of the Spirit. Within the body of Christ and within a marriage, the integrity and wholeness depend on the same thing: abiding in Christ and always allowing Him to be the head. We must constantly take on the mind of Christ in order to have successful marriages as well as thriving churches. When we do this, the fruit of the Spirit will prevail, keeping us healthy and one. We must strive to be in constant fellowship with Christ and each other, resisting fellowship with the world.

Kwanza Fisher is an educator in the greater Atlanta area where she enjoys a good hike, current events, and reading and writing about the Christian journey. She graduated with a Bachelors in East Asian Studies from Wellesley College and has a passion for international affairs from a Biblical perspective.