Therefore we grant that marriage is a type of Christ and the Church, and a sacrament, yet not divinely instituted, but invented by men in the Church, carried away by their ignorance both of the word and of the thing. Which ignorance, since it does not conflict with the faith, is to be charitably borne with, just as many other practices of human weakness and ignorance are borne with in the Church, so long as they do not conflict with the faith and with the Word of God. But we are now dealing with the certainty and purity of the faith and the Scriptures; so that our faith be not exposed to ridicule, when after affirming that a certain thing is contained in the Sacred Scriptures and in the articles of our faith, we are refuted and shown that it is not contained therein, and, being found ignorant of our own affairs, become a stumbling-block to our opponents and to the weak; nay, that we destroy not the authority of the Holy Scriptures. For those things which have been delivered to us by God in the Sacred Scriptures must be sharply distinguished from those that have been invented by men in the Church, it matters not how eminent they be for saintliness and scholarship.

So far concerning marriage itself. But what shall we say of the wicked laws of men by which this divinely ordained manner of life is ensnared and tossed to and fro? Good God! it is dreadful to contemplate the audacity of the Roman despots, who wantonly tear marriages asunder and again force them together. Prithee, is mankind given over to the wantonness of these men, for them to mock and in every way abuse and make of them whatever they please, for filthy lucre's sake?

Works of Martin Luther — Part 192

There is circulating far and wide and enjoying a great reputation, a book whose contents have been poured together out of the cesspool of all human traditions, and whose title is "The Angelic Sum,[138]" though it ought rather to be "The More than Devilish Sum." Among endless other monstrosities, which are supposed to instruct the confessors, while they most mischievously confuse them, there are enumerated in this book eighteen hindrances to marriage[139]. If you will examine these with the just and unprejudiced eye of faith, you will see that they belong to those things which the Apostle foretold: "There shall be those that give heed to spirits of devils, speaking lies in hypocrisy, forbidding to marry." [1 Tim. 4:1 ff.] What is forbidding to marry if it is not this--to invent all those hindrances and set those snares, in order to prevent men from marrying or, if they be married, to annul their marriage? Who gave this power to men? Granted that they were holy men and impelled by godly zeal, why should another's holiness disturb my liberty? why should another's zeal take me captive? Let whoever will, be a saint and a zealot, and to his heart's content; only let him not bring harm upon another, and let him not rob me of my liberty!

Works of Martin Luther — Part 192