There really is no such thing as “Christian marriage” as the term is commonly used. “Christian marriage” is a vain, romantic, unbiblical conception. “Christian marriage” is a fiction. There is no more an institution of “Christian marriage” than there is a “Christian nation” or a “Christian lawyer” or a “Christian athlete.” Even where such terms are invoked as a matter of careless formulation and imprecise speech, they are symptoms of a desire to separate Christians from the common life of the world, whereas Christians are called into radical involvement in the common life of the world. To be sure, there are Christians who are athletes and those who practice law, and there are Christians who are citizens of this and the other nations. But none of these or similar activities or institutions are in any respect essentially Christian, nor can they be changed or reconstituted in order to become Christian. They are, on the contrary, realities of the fallen life of the world. They are inherently secular and worldly; they are subject to the power of death; they are aspects of the present, transient, perishing existence of the world.
It is the same with marriage. Marriage is a fallen estate. That does not mean that it is not an honorable estate, but only that it is a relationship subject to death. It is a relationship established in and appropriate for the present age, but not known or, more precisely, radically transcended and transfigured in both the Creation and the Eschaton - in both the beginning and the end of human history.”—William Stringfellow, “Instead of Death.” (via locusimperium)