There is a real and strong offense inherent in God’s Law and Gospel, rightly divided. Those who find their god in their own bellies don’t care about it, but many others, who pay attention to spiritual matters, find the preaching of Law and Gospel to be offensive. This includes many “in Israel,” that is, church members.
Therein is the reason why there is such division in outward Christianity. If we insist on recovering, preserving and teaching the pure Gospel of Christ, we will risk further outward fracturing of Christianity. There will always be some — even many who find it offensive. In that sense, the Reformation has indeed had a part in the divisions that are so apparent. Is Christian unity so precious that we should seek to buy it with our certainty of salvation? I hope not.
A new “gospel” message has been arising in many churches, in which the only “false” teaching is one that discriminates between righteousness and sin, between saved and unsaved. Some churches have found that this message sits well with a great many people, especially if it’s seasoned with a generalized nod toward the Golden Rule. “God will save everyone who tries their best.” And the ranks of those churches swell to bursting. No offense there.
On the other hand, there are also divisions in outward Christianity that have no bearing upon our certainty of salvation, nor any relation to the teaching of God’s Word. Those sad divisions can be healed in only one way: by recovering, preserving, and teaching the pure Gospel of Christ. In other words, through Reformation.
This, from Luther in 1531:
For many years, it was common experience at many gatherings that preaching was done to please everyone and cause offense to nobody. But the fact is, if you remove the offense and the obstacle, then Christ is lost. For right from the beginning when this man came into the world to show himself, there was opposition and taking of offense. Yes, say the pope, the bishops, the wise, and the mighty of this world, we will not tolerate this. Very well, are you angry? Then suppress it. Christ came to the Jews. He did not ask them beforehand whether or not he should come. This started such a stir in their land that they could not suppress it. Now he has come to us through his gospel, without our knowledge or will, and has also started a great uproar. Are you angered? Then oppose it. Are you wise? Then speak your mind. There are many who want to resolve the matter by human wisdom, but that remains to be seen. If they’re going to resolve this, bring an end to division and offense, achieve tranquility and unity, as they suppose, then I will scratch this text. Christ himself says in Matthew 10:34, “Think not that I am come to send peace on earth: I came not to send peace, but a sword.” Therefore, it will likely be and remain, as Simeon states, “This child is set for the fall and rising again of many in Israel.” On the other hand, many will rise because of him and be saved. Those who try to resolve this matter through human wisdom will accomplish nothing; rather, they will fall, never to rise, and be smashed because of it. For they try to make Christ different from what God ordered and ordained.
— Luther’s House Postil vol. 1, first sermon for “First Sunday after Christmas”