From Martin Luther’s “A Sermon on Preparing to Die” (from 1519):

Death looms so large and is terrifying because our foolish and fainthearted nature has etched its image too vividly within itself and constantly fixes its gaze on it. Moreover, the devil presses man to look closely at the gruesome mien and image of death to add to his worry, timidity, and despair. Indeed, he conjures up before man’s eyes all the kinds of sudden and terrible death ever seen, heard, or read by man. And then he also slyly suggests the wrath of God with which he [the devil] in days past now and then tormented and destroyed sinners. In that way he fills our foolish nature with the dread of death while cultivating a love and concern for life, so that burdened with such thoughts man forgets God, flees and abhors death, and thus, in the end, is and remains disobedient to God.
So what should we do about the dread of death, Magister Luther?
We should familiarize ourselves with death during our lifetime, inviting death into our presence when it is still at a distance and not on the move. At the time of dying, however, this is hazardous and useless, for then death looms large of its own accord…The power and might of death are rooted in the fearfulness of our nature and in our untimely and undue viewing and contemplating of it.