As gay marriage becomes the law of the land in many jurisdictions and, very likely in the near future, in the whole country, some Christians are saying, well, marriage is a religious function anyway. Let the state do whatever it wants in regards to redefining marriage. Or, better yet, let it get out of the marriage business. We Christians will uphold real marriage, and we don’t need the state to let us do that.
Well, that might work if we were all Roman Catholics. The church of Rome used to control and regulate all marriages. But the Reformers took issue with that, insisting that the state should be in charge of marriage.
First, marriage is not a sacrament. That means non-Christians no less than Christians can enter into this estate. True, God is the one who joins together. But the estate of marriage is a critical way that God governs His earthly kingdom.
Second, it follows that, according to the Reformers, the regulation of marriage specifically belongs to civil magistrates and NOT to the church. This is reflected in the Lutheran Confessions at several points, perhaps most explicitly in the Treatise on the Power and Primacy of the Pope:
77] There remains the jurisdiction in those cases which, according to canonical law, pertain to the ecclesiastical court, as they call it, and especially in cases of matrimony. This, too, the bishops have only by human right, and that, not a very old one, as appears from the Codex and Novellae of Justinian that decisions concerning marriage at that time belonged to the magistrates. And by divine right worldly magistrates are compelled to make these decisions if the bishops [judge unjustly or] are negligent. The canons also concede the same. Therefore, also on account of this jurisdiction it is not necessary to obey bishops.
78] And, indeed, since they have framed certain unjust laws concerning marriages, and observe them in their courts, there is need also for this reason to establish other courts. For the traditions concerning spiritual relationship [the prohibition of marriage between sponsors] are unjust. Unjust also is the tradition which forbids an innocent person to marry after divorce. Unjust also is the law which in general approves all clandestine and underhanded betrothals in violation of the right of parents. Unjust also is the law concerning the celibacy of priests. There are also other snares of consciences in their laws, to recite all of which is of no profit. It is sufficient to have recited this, that there are many unjust laws of the Pope concerning matrimonial subjects on account of which the magistrates ought to establish other courts.
Now perhaps the church might have to retake control, at least over its members. And, has been observed, this would also be the chance to re-assert its other teachings about marriage that have largely been forgotten, as in rejecting divorce.
But the state does have legitimate authority over marriage. This poses a theological problem for Protestants and perhaps especially for Lutherans, since our confessional position is laid out so fully. Could someone work out the parameters for this, taking into account the Doctrine of the Two Kingdoms?