Truth and doctrine, are to be preached always

Truth and doctrine, are to be preached always, openly, and firmly, and are never to be dissembled or concealed; for there is no offence in them; they are the staff of uprightness.—And who gave you the power, or committed to you, the right, of confining the Christian doctrine to persons, places, times, and causes, when Christ wills it to be proclaimed, and to reign freely, throughout the world? For Paul saith, "the Word of God is not bound," (2 Tim. ii. 9,) but Erasmus bounds the word. Nor did God give us the word that it should be had with respect of places, persons, or times: for Christ saith, "Go ye out into the whole world,": He does not say, as Erasmus does,—go to this place and not to that. Again, "Preach the Gospel to every creature." (Mark xvi. 15.) He does not say—preach it to some and not to others. In a word, you enjoin, in the administration of the word of God, a respect of persons, a respect of places, a respect of customs, and a respect of times: whereas, the one and especial part of the glory of the word consists in this,—that, as Paul saith, there is, with it, no respect of persons; and that God is no respecter of persons. You see therefore, again, how rashly you run against the Word of God, as though you preferred far before it, your own counsel and cogitations.

—Martin Luther. The Bondage of the Will (Kindle Locations 676-684).