"A man shall leave his father and mother." What does it mean?

What does the Bible mean when it says “a man shall leave his father and mother” and that him and his wife will become "one flesh"? In short, the Bible sees marriage as creating a new single unified body out of two individual bodies. The passage is: “For this reason a man shall leave his father and mother and cleave to his wife and the two shall become one flesh” (Gen. 2:24). It’s easy to read this as a colorful portrayal of how two people come together in marriage and lead a life of partnership and cooperation, but the traditional way Christians have understood this passage is much deeper than that. The passage actually explains not only the Christian view of marriage but the nature of God and of love itself.

What does the bible say about weddings?

It is important to put this passage into the context of ancient people. Modern people tend to think of the physical and spiritual as opposites. Something can be “just” physical or it can be “just” spiritual. But ancient people did not think this way. All ancient people, in all cultures, believed that the physical and spiritual were deeply connected. They didn’t think that anything was just physical, but that all physical things had a spiritual part to them, and also that spiritual things had a physical part to them. The spiritual and the physical could not be separated in any way that would make sense. This was true for all ancient people – pagans, Christians, and Jews alike. This view was at the heart of their idea of a wedding, which they viewed as a ritual action that changed the nature of the two people involved.

In contrast, modern people today tend to think of a wedding as a kind of contract or agreement. Looking at modern marriages, you would think that the Bible said, ”For this reason a man shall leave his father and mother and form a mutually beneficial partnership with his wife and the two shall hold one agreement.” That would be the language of contracts. And indeed, modern weddings tend to include vows or other promises – which is essentially what a contract is. This is also why people often see divorce as a normal and healthy option. If marriage is just a contract, why can’t the contract simply be dissolved?

Leave and cleave

The Bible does not use any of this contract language. Instead it uses language that is both physical and spiritual. It says that a man will “cleave” to his wife, and that the two will become “one flesh”. In other words, that the act of sex actually creates a new physical and spiritual situation: two people have in fact become one person. The nature of the two people who have entered into the relationship has now physically changed. But how can they become one body through the act of sex? A good analogy is to a lock and a key. You’ll notice that a lock and a key are not really two different mechanisms, they’re two different parts of the same mechanism.

In this traditional Christian view of marriage, marriage is not an alliance or a contract. The wedding is not even completed fully by the wedding ceremony: the act of sex is what completes the process of wedding the two people together, what used to be called “consummating” the marriage. The physical union creates a spiritual change: two people have become “one body” – which is a much deeper, more profound union than two people “getting on the same page” about something through agreement or by making a contract. We see this later in the Bible when St. Paul says that “husbands ought to love their wives as their own bodies. He who loves his wife loves himself. Indeed, no one ever hated his own body, but he nourishes and cherishes it” (Eph 5:28-29; emphasis mine). The ancient Christian view of marriage is that of a man and a woman becoming unified not in a metaphorical sense, but as literally becoming the same flesh, just in separate bodies.

God is more married than we are!

What is the spiritual significance of this unity? It has to do with understanding the nature of God. One thing that many people struggle to understand is the Christian notion of the Trinity: that God is both one God but also three persons – the Father, Son, and Holy Spirit. Sometimes this is explained as a “paradox” that has to be taken ”on faith”, but that is not how ancient Christians understood it. They believed in the Trinity not because it was a paradox but because it made sense – specifically, it made sense out of the things they saw in the life of Christ and in the writings of scripture. Much ink has been spilled over the centuries explaining exactly how the Trinity works, but most people aren’t that interested in those technical explanations. I think a better way to explain the Trinity is by answering the question, “why does it matter?”

The reason that the Trinity matters is because it explains another important passage in the Bible: the phrase “God is love” (1 John 4:8). This passage doesn’t mean “God is loving” it means “God is love”. How can God be love itself? A simple way to explain it is that God, in his very nature, consists of multiple persons that exist in loving relationship with one another. The Father loves the Son, the Son loves the Father, the Holy Spirit loves the Son, and so forth. They all love each other with perfect love, and these loving relationships are the foundation of what God is: namely, love. Part of the reason they have perfect love for one another is that they aren’t really three separate people but are completely and totally one God. They share the same essence (as the early Christians put it) so much so that it’s correct to talk about them as “one God” rather than “three gods”. And because these loving relationships form the nature of God’s inner life, it’s correct to say that God is love.

The Bible says families are a reflection of God’s Trinity

What does this have to do with marriage? Earlier in Genesis, prior to the verse about a man leaving his father and mother, there is a passage that helps explain this. When God goes to create mankind, he says, “let us make man in our image” (Gen 1:26). While there are many ways in which mankind is made in the image of God, one of them is the way in which a human family is a kind of reflection of the union of the Trinity.

An individual person is one person but when joined to a spouse in this physical way we’re talking about, the two spouses become one body in a real, physical sense. This physical unity creates a spiritual unity between them as well, such that we can call the two persons ”one body”. And when children are born, those children are literally made out of the same “stuff” as their parents. It’s important to remember that your body is something your mother grows for you out of her own body – you are made out of the physical union of your parents.

In this way a human family is a kind of faint reflection of the Trinity. A family is many people, each preserving their own distinct identity, but is also joined at the level of their fundamental substance – in this case, their physical bodies. The family members’ love for one another is a natural, biological overflow of the fact of their physical unity.

Obviously, not all families are perfectly loving, and unfortunately there are families where there isn’t much love, but that is a corruption of what God intends. At the baseline, physical level, sexual activity leads to feelings of affection and unity. Likewise, parents have an innate predisposition of love for their offspring. While these instincts can be ruined by bad actions over time, this state of loving unity is the default – it’s biologically hardwired into us.

There’s an important disclaimer here, which is that a human family is not a perfect analogy for the Trinity. If you think that it is, you’ll get the wrong idea about the Trinity. You might start to think that “God” is less like a singular being and more like the name of a family of separate individuals, but that’s not correct. The Trinity is like a family but it’s much more intense than that: the three persons are even more unified than a family is. They’re not merely “made of the same stuff”, they’re almost more unified than we can imagine, such that (again) it’s correct to call the Father, Son, and Holy Spirit “one God”. If that doesn’t make sense completely, that’s okay. The full explanation is, as I mentioned, more technical, but for now it’s sufficient to say that a human family is a good analogy or starting place for understanding the nature of God as Trinity – and God as love.

Conclusion: Christian marriage as a reflection of God

Unlike a modern understanding of a contract or alliance, an ancient Christian understanding of marriage was based on this idea of the real, physical unity of the spouses in a way that changes their being. This is why the oldest Christian traditions call marriage a “sacrament”, which is a word referring to things that have this spiritual-and-physical combination. This complete union of a man and a woman is a dim reflection of the nature of God: God’s very nature is that he exists as a perfect community of love, which is the ideal for a human marriage.

It is especially significant that this union is (ordinarily) life-giving: that the intense physical desire and passion that lovers feel for one another actually leads to the creation of new life (in the form of children) is a powerful image of God’s life-giving love for human beings, both in his creation of mankind in the first place but also his work to free mankind from death through his resurrection from the dead.