Marriage is more than your love for each other. It has a higher dignity and power, for it is God's holy ordinance, through which he wills to perpetuate the human race till the end of time. In your love you see only your two selves in the world, but in marriage you are a link in the chain of the generations, which God causes to come and to pass away to his glory, and calls into his kingdom.
In your love, you see only the heaven of your own happiness, but in marriage you are placed at a post of responsibility towards the world and mankind. Your love is your own private possession, but marriage is more than something personal—it is a status, an office. Just as it is the crown, and not merely the will to rule, that makes the king, so it is marriage, and not merely your love for each other, that joins you together in the sight of God and man.
As high as God is above man, so high are the sanctity, the rights, and the promise of marriage above the sanctity, the rights, and the promise of love. It is not your love that sustains the marriage, but from now on, the marriage that sustains your love.
– Dietrich Bonhoeffer, Letters and Papers from Prison, 7.