The tasks of a pastor of Jesus Christ are many, difficult, and demanding. The most difficult and demanding task of all – beyond question – is the task of proclaiming the pure doctrine of the Gospel of Christ and at the same time exposing, refuting, and rejecting teachings that are contrary to the Gospel. A pastor who does this will discover by experience the truth of the old saying: “Telling the truth makes enemies” (Latin: Veritas odium parit)….
Worldly people and all false Christians cannot help but attack those who teach a faith and doctrine different from theirs. These fake Christians regard those with sound doctrine as “disturbers of the peace” – peace-hating, quarrelsome, and nasty people. These unfortunate people have no idea of the blindness that surrounds them. They do not know how gladly the boldest champions of Christ wish to keep peace with all people, how much they would prefer to keep silent. These fake Christians do not know how hard it is for the bold champions to go public and become targets for the hatred, enmity, slander, scorn, and persecution of people. However, they cannot help but confess the truth and at the same time oppose error. Their conscience forces them to do this because such behavior is required of them by the Word of God….
Besides, righteous preachers remember that the Church is not a kingdom that can be built up in peace. It is located within the domain of the devil, the prince of this world. Accordingly, the Church has no choice but to be at war. It is the Church Militant and will remain such until the blessed end. Whenever a church appears to be not a militant church but a church at ease, that is a false church. You can rely on it!…
Keep these facts stored up in your memory, my dear friends. If you wish to be a faithful servant of Christ, you cannot possibly do so without striving and fighting against false doctrines, a false gospel, and false belief. In the view of worldly people, your lot will not be particularly enviable. Even wise Sirach says, “If you come to serve the Lord, prepare your soul for temptation” (Sirach 2:1). What he means is this: It is impossible for you to escape affliction if you wish to be a faithful servant of God. Anyone who is without affliction may be ever so passionate about fulfilling the duties of his office, yet his passion is nevertheless not of the right sort. Where there is genuine passion, not only does one plant and build, but the workers will also have the sword strapped to their waist, going out to wage the wars of the Lord….
So ignore any view that people would express in opposition to your teaching. Doing this will let your cause shine with even greater luster in heaven. On the Last Day, God will say to you, “Well done, good and faithful servant. You have been faithful over a little; I will set you over much. Enter into the joy of your master.” We will be refreshed when we quit this wicked world and the association of false Christians who shamefully slander our best efforts, calling them the worst horrors. Then our Lord Jesus will say, “Well done! Good joy. You did not look for ease and comfort. Rather, you focused on keeping what was entrusted to you.”
– Law and Gospel, Readers Edition, p. 293-295