Why Should Christians Care About the Definition of Marriage? Understanding Important Bible Passages

This article first appeared at the Ethics and Religious Liberty Commission.

I still remember the first time I heard a Christian question why it was bad for the government to change the legal definition of marriage. I was an associate pastor in Washington state, and in 2012 the state voted to allow legal same-sex marriage, three years before Obergefell legalized it nationwide. As people were discussing how they felt about changing a definition that had held firm for all of human history prior, a member of my church shared that she didn’t understand why most Christians were against the state changing the definition of marriage. She expressed that she did understand that Christians should personally be opposed to same-sex marriage given the Bible’s clear teaching on marriage, but she did not see any compelling reason that we should care about what the government allows or defines as marriage.

A decade later, there are many reasons we could clearly point to, ways that same-sex marriage has changed our culture. To name a few: legal battles for conscience protections for small businesses, many religious adoption agencies closing down as they were forced to change their firmly held religious beliefs or stop helping children, the cascade of gender dysphoria that is especially hitting our teens and young adults, and gender and sexuality options that are now being taught openly in our public schools, even to elementary students. But as clear as some of those reasons are for concern, as the Senate now moves toward repealing the 1996 “Defense of Marriage Act,” is there a theological reason that Christians should care about the definition of marriage in our broader culture? To put it another way, is there a “gospel reason” that Christians cannot support the legal definition change of marriage?

A theology of marriage 

Jesus was asked difficult theological questions about marriage by his disciples. While the issue his followers asked about in Matthew 19 and Mark 10 may have been directly about divorce, the answer Jesus gave continues to echo down to us today, answering questions about why Christians should care about the definition of marriage. Just in the first phrase of his reply, Jesus shows why marriage is only truly between a man and a woman: “He answered, ‘Have you not read that he who created them from the beginning made them male and female’” (Matt. 19:4) Jesus takes the disciples—and us—way back. He pulls them back to the Garden of Eden when humanity, and marriage, were first created. 

The Lord clearly lays out that God created Adam as a male and Eve as a female, which will become significant the deeper we dig into why God created humans and marriage the way that he did. Jesus also reminds us that God is the Creator, which means that he not only knows what is best for human flourishing, but also that we do not get to make up our own definition for institutions that God has created such as marriage. If we do so, it will have disastrous consequences as we try to “un-god” God, and “god” ourselves with the powers of creation. Because God created it, marriage was never ours to change.

Next, Jesus explains more about why marriage is deeper and more significant than we often give it credit for, by quoting Genesis again and then adding his own divine thoughts. He explains: “’Therefore a man shall leave his father and his mother and hold fast to his wife, and the two shall become one flesh’ . . . So they are no longer two but one flesh. What therefore God has joined together, let not man separate” (Matt. 19:5-6). As Jesus explains the significance of marriage here, he gives us huge clues as to why same-sex marriage is not just a bad idea, but is not really marriage. When Jesus talks about marriage in terms of “man” and “wife,” he is not simply speaking to a different culture and time as if in the future, more progressive ideas could erase the way God originally created marriage. He brings the disciples back to creation to show them that the way we understand marriage must go back to when God first created it. Jesus shows us that there is profound significance in a husband and wife becoming “one flesh.” 

There is beauty, function, meaning, and even gospel pointers in marriage between a husband and wife. A man and woman in marriage are different and yet equal, separate and yet joined together as one. This cannot be done between a husband and husband or wife and wife. Not only do they not fit together in the same way physically, but in taking away the God-created differences between man and woman and replacing them with sameness, homosexual marriage also takes away the “one flesh” union that Jesus speaks of here. It is only in the differences of male and female (Matt. 19:4) that there can be the union of marriage (Matt. 19:5-6). Remember, Jesus started answering the disciples’ questions about marriage by asking, “Have you not read?” If Jesus were answering us today as we asked him about same-sex marriage, there is no doubt that he would say something along the lines of, “Have you not read?”, referring to either Genesis or the Gospels, and then, “What therefore God has not joined together, let not man join together.”

But I believe there is at least one more passage Jesus would bring us to with our same-sex marriage questions today. In Ephesians 5, we learn—astoundingly—that God’s design for marriage points to the gospel. As a common grace for both believers and unbelievers, God created marriage from the beginning of time to be something embedded in culture that would point to the love of Jesus for his bride. This is often hard for us to grasp because we don’t mirror this as clearly as we should. But in the union between a man and a wife, there is a pointer to the union of Jesus with his people. The marriage covenant points to the New Covenant. 

Near the end of the longest New Testament passage on marriage Paul explains, “This mystery is profound, and I am saying that it refers to Christ and the church.” (Ephesians 5:32) Every marriage between a man and a woman points in some way to Jesus and the gospel, for those who have eyes to see it, even if only in the fact that there is a deep union. The only question is, how clear and well-focused or how tarnished is that picture? But same-sex marriage does not create that picture of the gospel at all. God never intended it to, and it can’t, because it is in our very differences that we find union.

Conclusion

Given the cultural winds, the ideology that leads to the celebration of same-sex marriage and other gender identity issues will continue to gain ground in hearts and minds. But for Christians, while we love those involved in homosexuality as people made in the image of God, we cannot celebrate or endorse same-sex marriage, and we should encourage our legislators to do the same—for the good of families and our wider society.

Because God embedded marriage into culture as a quiet pointer to the covenant love of Jesus for his bride, Christians have more work to do in sharing our faith and discipling our kids and young believers. We have to now build a broader foundation, including the fact that God has clearly defined marriage and that it is not best for our societies or gospel witness when we tamper with it. Yet, in this context, while we have more urgent opportunities to disciple others in how God created marriage, Christian marriages can grow. We can repent of and grow in any ways that we have not pointed to Jesus in our marriages like we should. As confusion grows in what marriage actually is, Christians have an opportunity to shine brighter through living in their marriages as better representatives of Jesus—which starts in our homes and in our churches. While our broader culture becomes less clear about marriage, may we continue to proclaim that the covenant of marriage as God has designed points to the New Covenant of the gospel. And as the basic accepted definition of marriage changes, may we say with our joyful covenant-keeping what is being unsaid all around us.