Paul makes a case in Ephesians 5:21–33 that what is essential in conjugal love is rooted in a “man leaving his father and mother to be united with his wife” (5:31). This takes the reader back to Genesis and the created order. But what makes this unique is not the appeal to origins and the pre-fallen state but rather the application of this principle to the union of God with humanity in Christ, the true Beloved (Mark 2:19).
Here we encounter the central core of what is going on in this text: divine mystery. This means that what Paul is saying here could not be understood before Christ came. If this teaching is not “new” then the point is lost. Marriage is not without a divine and historical foundation, thus it is rooted in Genesis. But it is new here in the sense that no one before Christ could have understood marriage in the fullness of what is being taught by Paul. This is why marriage is understood sacramentally by the Roman Catholic Church. I do not believe marriage meets the essential biblical understanding of a sacrament. At the same time I must tell you that I would rather it be treated as a sacrament, in the very best sense of the word “sacred sign,” than as a convenience or a simple church ceremony, which is the way most evangelicals receive it in the present age. Marriage, for Christians, is living in a divinely ordered relationship according to the love of Christ. Paul says “this is a very great mystery” precisely because he is not primarily referring to marriage between a husband and his wife but rather to “Christ and the church” (5:32). This is what I believe most of us miss when we read this text.
The church fathers had much to say about marriage understood in this way. Listen to Clement of Alexandria: “The spiritual man will prefer neither children, nor marriage, nor parents to his love for God and righteousness in life. To such a man of God, after conception, his wife is a sister and is treated as if of the same father.”
Tertullian writes that marriage is “one hope, one desire, one discipline, and one and the same service. Both are brethren; both are fellow servants. There is no difference of spirit or of the flesh. Rather, they are truly two in one flesh. Where the flesh is one, the spirit is one too.”
And the Apostolic Constitutions (compiled c. 390) says: “‘The two shall be one flesh.’ For the husband and wife are one in nature, in consent, in union, in disposition, and the conduct of life. However, they are separated in sex and number.”
Marriage was designed as a divine covenant. Everyone agrees with this if they read and follow Scripture. There is no Protestant and Catholic disagreement. What I think we can all should accept is that marriage is also a sign of the covenant that God made with humanity. In Christ the man and his wife are to live out this great mystery in a covenant of love, fidelity and fruitfulness.
Marriage is a covenant relationship in which each person loves the other unconditionally. It is not just a contractual relationship in which I promise to love you if you love me. The principal goal of marriage is not the procreation of children, it is also the mutual love of husband and wife. Children are a blessing and the fruit of divine love in Christian marriage. As I have also argued marriage has an important community dimension, namely that couples become living signs of how God loves us and how much God wants to embrace us as family. Christian marriage assures a couple's ability to sustain close intimate relationship thus it rightly assumes a relationship to Christ and his church. Regardless of how the culture defines marriage Christians must obey God, not man.
The wife submits to her husband as “the church submits to Christ” (5:24). Christ does not force the church into submission. He loves her and leads her as a self-giving servant who lays down his life out of love. She lovingly hears his voice and follows because of his sacrifice. This happens because “husbands love their wives [as] Christ loved the church and gave himself up for her” (5:25). The wife will not find it difficult, in normal circumstances (human sin can always break human relationships), to follow her husband's lead because of his devotion to her, a devotion that is found only in the mystery of Christ’s love for his church (5:25–30).