What does "two shall become one flesh" mean?

I. Scriptural Origin and Foundational Context

The phrase “two shall become one flesh” first appears in Genesis 2:24: “For this reason a man will leave his father and mother and be united to his wife, and they will become one flesh.” This foundational verse is echoed throughout Scripture, notably in Matthew 19:5–6 and Ephesians 5:31. In both Old and New Testament references, this phrase underscores God’s design for marriage as a union that transcends physical connection and includes emotional, spiritual, and covenantal dimensions.

Genesis, one of the earliest books preserved in ancient Hebrew manuscripts (with fragments discovered among the Dead Sea Scrolls), portrays creation in a manner consistent with purposeful design: humankind is formed with intentional roles and relationships. When the text speaks of a man leaving his father and mother, it signals a new, distinct family unit. The uniting into “one flesh” emphasizes the completeness and permanence intended in this divinely instituted bond.

II. Original Language Insights and Literary Usage

In Hebrew, the term translated as “flesh” (basar) can refer to a person’s entire being—physically, emotionally, and relationally. Thus, “one flesh” carries a sense of full, inseparable unity. This concept is not momentary; it reflects an ongoing state of identity shared between husband and wife.

In the New Testament Greek, the idea remains consistent. When Jesus quotes Genesis 2:24 in Matthew 19:5–6 (BSB: “the two will become one flesh. So they are no longer two, but one flesh”), He reaffirms that God’s intention is a lifelong, unbreakable union. The apostle Paul repeats this teaching in Ephesians 5:31, connecting it to the relationship between Christ and His Church.

III. Theological Significance of “One Flesh”

1. Spiritual Unity

Scripture portrays marriage as a covenant, mirroring God’s own faithfulness. This unity extends beyond a physical bond, reflecting a shared spiritual journey in which the couple grows together in their devotion to God. Ephesians 5:32 likens the marital relationship to Christ’s union with the Church, indicating a profound mystery and a spiritual depth.

2. Emotional Bond

The concept of “one flesh” recognizes that marriage weaves together the emotional lives of two individuals. This unity fosters mutual support in trials, shared joys in blessing, and an ever-deepening companionship. Such closeness rests upon honesty, open communication, and sacrificial love.

3. Physical Union

“One flesh” certainly includes the physical relationship between husband and wife (1 Corinthians 7:3–5). This aspect is designed as both an expression of oneness and a means for procreation. Within a larger biblical framework that emphasizes purity and faithfulness, physical union is a holy and exclusive bond.

4. Covenantal Permanence

Scripture consistently portrays marriage as intended for life (Malachi 2:14–16). The phrase “one flesh” communicates not a temporary arrangement, but a permanent covenant under God. Jesus underscores this point in Matthew 19:6 by stating, “Therefore what God has joined together, let man not separate.”

IV. Ethical and Behavioral Implications

1. Respect and Sacrifice

In Ephesians 5:25, husbands are told to love their wives as Christ loved the Church—selflessly and sacrificially. Wives, likewise, are encouraged to respect their husbands (Ephesians 5:33). These teachings confirm that living as one flesh requires mutual honor and willingness to serve each other.

2. Family and Community

In becoming “one flesh,” a husband and wife form a new familial bond. This relationship supports the stability of the broader community. From a behavioral science perspective, healthy marital unity often leads to supportive environments for children, strengthening the relational fabric of society.

3. Accountability and Integrity

The covenant nature of “one flesh” reminds believers that a marriage vow is first made before God. This accountability fosters integrity, discouraging infidelity, and promoting transparency. When the married couple sees themselves as one organism bound by divine design, it reshapes how conflicts are handled and how forgiveness is sought and granted.

V. Apologetic Reflections on Historicity and Reliability

1. Manuscript Evidence

The Genesis account undergirds the doctrine of marriage. Some of the oldest extant manuscript fragments (e.g., the Dead Sea Scrolls) confirm the consistency of Old Testament texts, attesting that Genesis 2:24 has been faithfully preserved. Scholars, drawing on manuscript traditions, highlight that this passage has remained virtually unchanged over millennia.

2. Archaeological and Cultural Consistency

Ancient Near Eastern archaeology reveals cultures that recognized marital unions as covenantal. While the biblical concept of marriage uniquely involves God’s creative design, contemporary ancient texts and inscriptions affirm that marriage and family life were central to society. This consistency with external evidence supports the biblical depiction of marriage practices.

3. Design Evidences

From an intelligent design perspective, human biology, psychology, and sociology point to purposeful male-female complementarity. Scientific findings in fields such as physiological bonding (e.g., the hormone oxytocin’s role in a couple’s emotional attachment) illustrate the idea of two lives intricately woven together. This natural harmony aligns with the biblical statement that husband and wife become “one flesh.”

VI. Broader Biblical Connections

1. Union of Christ and the Church

In Ephesians 5:32, Paul calls the union of a husband and wife a “profound mystery” and directly relates it to Christ’s oneness with the Church. This connection shows how marriage displays God’s sacrificial love in a tangible, earthly relationship.

2. Redemptive Foreshadowing

Throughout Scripture, covenant imagery—be it marriage, temple worship, or nationhood—ultimately directs attention to God’s saving work. The fidelity of spouses under the bond of “one flesh” can reflect Christ’s unwavering commitment to redeem His people through His death and resurrection.

VII. Practical Application and Conclusion

When two individuals enter marriage with a commitment to becoming “one flesh,” they participate in a covenant reflective of God’s own relational nature. This unity is displayed in shared goals, sacrificial love, and unwavering faithfulness. It is woven into the fabric of Scripture and remains a living illustration of how the faithful character of God finds expression within human relationships.

Marriage, thus, is not a social contract alone; it is a privileged fellowship designed and upheld by the Creator of the universe. The phrase “two shall become one flesh”—while brief—carries profound meaning, shaping the way couples live, churches function, and society flourishes. The biblical revelation, supported by consistent manuscript testimony and external archaeological and cultural confirmations, stands as a foundational truth that guides believers in understanding and living out God’s intended blueprint for marriage.