In a sermon on 1 John 4, Luther addresses those pastors and people who wrongly imagine that they can preach and listen only to the Gospel apart from the rebuke and admonition of the Law:
YOU have often heard and are now hearing the complaint, which is universal in all the world, that when human beings hear the preaching of faith about the remission of sins, they embrace it, because it is a delightful preaching: God has sent His Son for you. But when it is said that you must adorn your faith to the praise of God, and sins are rebuked, no one wants to hear anything more.In towns everywhere, people distinguish among preachers. “This one is a fine preacher, who talks about grace and mercy; and what is even finer, he does not scold anyone or frighten people.” That is the way people commonly talk and act. If he does rebuke [sins], they undertake to have him removed. Therefore, many [of these preachers] have returned to us.
When you are scolded as a usurer, adulterer, or whatever kind of swine you are, or [it is said] that a peasant, a townsman, or a nobleman is godless, no one will suffer that. “But if I am a usurer, adulterer, swindler, and [the preacher] does not scold me, ah, what a pious man he is!”
[Are you] really righteous because I [do not] rebuke your vices? Then let the devil be [your] preacher. If I see peasants, townsmen, noblemen and do not chastise them, then I will go to the devil along with you. For [God says in] Ezekiel 3 [:18]: “I will require [their] blood at your [hands],” and they themselves will go to the devil. You shall give an account of yourself. I will not be responsible for that in the hour of death or of judgment. Rather, I shall declare what is contrary to the commandment, and then if you do not obey, you do it at your own peril.
. . . Surely an upright [Christian] gladly hears an admonition to faith, not to be greedy or a usurer, and he amends himself. I would want a brother to admonish me when I go astray. But they refuse to tolerate anyone who rebukes them [even] in general. When I say that usurers belong to the devil, why do you cry out? It is because you yourself are guilty. If you want to know which dog has been struck, it is the one who cries out.8 Therefore, you are accusing yourself, if you grumble, and are defaming yourself. As Cicero says, when vices are rebuked in general terms, whoever becomes angry at it shows himself to be guilty.
Whoever cannot bear it when unbelief is rebuked along with the fruits of unbelief, he is most certainly the dog who has been struck. But this is the purpose for which they want to misuse the Gospel: that they may do whatever they want, and the preachers should confirm it and so be cast down to hell along with them, or else we should nullify the Gospel and the ministry [of the Word], etc., [saying,] “Oh, it is all the same; do whatever you want and you will be saved!”
The Word must be unbound [cf. 2 Tim. 2:9]. It must be freely preached. Human nature has been corrupted by unbelief, which brings its fruits along with it. Therefore, sins must be rebuked, as in the Ten Commandments, etc. If you don’t want to listen to God, then don’t!
Luther, Martin. “Sermon for the First Sunday after Trinity, 1 John 4:16–21.” Luther’s Works: Sermons V. Ed. & trans. by Christopher Boyd Brown. Vol. 58. Saint Louis, MO: Concordia Publishing House, 2010, pp. 234–235.