“Although [polygamy] was lawful among the ancient fathers: whether it be lawful now also, I would not hastily pronounce.” ~ St. Augustine, The Good of Marriage
Redefining marriage is what Christianity has done throughout the ages. Indeed, even Martin Luther, the catalyst for the Protestant Reformation (though 53% of Protestants are unaware of that fact), wrote “I cannot forbid a person to marry several wives, for it does not contradict Scripture.” In 1650, the parliament of Nürnberg decreed that men could take up to ten wives for a brief period, and the Catholic Church adopted it. The Roman Catholic Church that put an official end to the practice of polygamy in the 12th century. The church redefined marriage.
Or what about endogamy (marrying only within a particular social group; the opposite of exogamy, which is marrying outside your particular social group)? Until 1967, Christian groups opposed exogamy in the form of marrying somebody of a different race (thus supporting endogamy). Names for these types of laws were often similar to Virginia’s oxymoronic “Racial Integrity Act,” and they were justified as defending the definition of marriage. If a black person loved a white person? Well, they can have their relationship, but why should we redefine marriage when it’s always been between two people of the same ethnicity?
The believers who made up the majority of the support for legislation like the Racial Integrity Act were quick to cite biblical passages in defense of their discriminatory definition of marriage, the most frequent of which was Phinehas and the curse of Ham. It should be noted that these laws would have prevented the marriage of Barrack Obama’s parents. Eventually, kicking and screaming, the church redefined marriage.
Or what about arranged marriages? These have been prevalent throughout history thanks, in large part, to the Hebrew edicts that marriage preserve property rights, as well as the tradition of marriage to tackle primarily financial issues. Often these marriages were conducted by proxy, in which somebody stood in for the groom. It is this tradition of marriage as a financial matter that gave us the idea of a dowry. Eventually, the church redefined marriage.
The list of sundry changes to the idea of marriage could quite literally go on forever. The fact that the church has a habit of changing the definition of marriage whenever it suited them or when it had to change in order to avoid looking like a cabal of eagerly discriminatory jerks (even though that was precisely what it was and in many ways still is) only shows their hypocrisy when they say that the definition of marriage shouldn’t be changed now. Even if they had never once changed that definition, it should still be changed in order to preserve equality, just like in centuries/decades past. While there is sometimes value to tradition that value is not absolute. If a tradition is discriminatory the tradition should be changed. We should not value tradition over avoiding discrimination.
And what’s more, who says “marriage” is the Christian’s word to define? Lots of different cultures and lots of different religions have completely different ideas of marriage, and those religions and cultures exist in this country (which cannot prefer one religion over another). Why is it the Christian definition that should get enshrined in our laws?
And who says Christians have to redefine marriage in the church? It’s not like the government will ever force a church to perform a wedding ceremony it doesn’t wish to perform. Churches can be as bigoted as they want (that they pursue that right should tell you something about their faith). Why should the Christian traditions be imposed on everybody else via the government?
The point is that religion has always redefined marriage when the need to do so became obvious (or when they were legally forced to because the need had become obvious to everybody else). Same-sex marriage is no exception.