In 1943 a German pastor by the name of Dietrich Bonhoeffer was locked up in a Nazi prison. Two years later on April 9, 1945, he was executed by Hitler’s SS troops.

In the relatively better days of 1943 life still held much promise for Bonhoeffer. While in prison some of his greatest joys were the things happening among his friends and family on the "outside."

Bonhoeffer received news that his niece, Renate, was to marry his best friend, Eberhard Bethge. With the interests of a pastor and love of an uncle, Dietrich wrote a wedding sermon for them from his cell.

In that message Bonhoeffer says something that goes against the grain of the entire modern world. To Eberhard and Renate he wrote: “From this day forward it will not be your love that keeps your marriage alive, it will be your marriage that keeps your love alive.”

What strange principle is this? What archaic wisdom did this "enemy of the German state" propose?

Bonhoeffer is saying that love between a man and woman does not strengthen their marriage. It is the marriage, rather, the covenant bond before God, that strengthens their love.

Human love finds its footing, its stride, it full potential in a climate of holy commitment. Outside of marriage romantic love is weak and shallow and languishing. Inside of marriage such love becomes thick and strong and true. One's knowledge of what marriage is and why it is and how it works does more for one's love than one's love does for marriage.

Marriage is something greater than the intentions of a couple to love each other. When a couple recognizes this greatness of marriage, their love is not diminished but expanded.

Think of a young man who wants to become King. He is not a great man merely because he has a fire in his bosom to rule over people. He becomes a great man when he lawfully is given the crown. His rule only becomes great when he justly fits it to the shape of the office. His study of monarchy will do more for his success than his instincts to rule.

So it is with human love and marriage. Marital love in its varied expressions - storge, philia, eros and agape - becomes beautiful, true and whole when it is made lawful by the office it is poured into: the honorable estate of marriage.

What is this estate of marriage? Marriage is a covenant between one man and one woman, an indissoluble union, for the procreation of children, for the prevention of sin, and for the mutual society, help and comfort of the spouses. Marriage is a life-giving holy covenant.

Listen in as God chastises the men of Israel in Malachi 2:14 “…the LORD was witness between you and the wife of your youth, to whom you have been faithless, though she is your companion and your wife by covenant.” These men had been discarding their wives through divorce. In pressing charges against them the Lord identifies marriage as a covenant.

What is a covenant? It is something profoundly different than a contract. In a contract you make arrangements to exchange goods or services for an agreed upon price. In a covenant you are not giving good and services, you are giving yourself. Thus in a marriage covenant everything that you are and will be is given to the other.

Now we see clearly why the Spirit says the relationship between Christ and the church is portrayed in the marriage union. In the gospel covenant of grace Christ does not just give us stuff - rain, sunshine, tomatoes and beer. He gives us himself in his humiliation as sacrifice for sinners and in his exaltation as resurrected and enthroned King. We are in covenant with him and so heirs of all that is his -primarily himself in death to sin and in everlasting life to righteousness.

Just as our love for Christ only flourishes in the legitimacy of being in covenant union with him by faith, so it is with marriage. Love is perfected in the formal bonds of covenant union. And because the greater union of Christ and his church precedes and will outlast all earthly marriage unions (Matt. 22:3) even the believing single person or widow or widower is not cut off from flourishing in holy love for they remain the chaste and faithful Bride of Christ.