“For if the trumpet give an uncertain sound, who shall prepare himself to the battle?”

Jean-Christophe (1904 - 1912), Journey's End: The Burning Bush (1911)
Context: God was not to him the impassive Creator, a Nero from his tower of brass watching the burning of the City to which he himself has set fire. God was fighting. God was suffering. Fighting and suffering with all who fight and for all who suffer. For God was Life, the drop of light fallen into the darkness, spreading out, reaching out, drinking up the night. But the night is limitless, and the Divine struggle will never cease: and none can know how it will end. It was a heroic symphony wherein the very discords clashed together and mingled and grew into a serene whole! Just as the beech-forest in silence furiously wages war, so Life carries war into the eternal peace.
The wars and the peace rang echoing through Christophe. He was like a shell wherein the ocean roars. Epic shouts passed, and trumpet calls, and tempestuous sounds borne upon sovereign rhythms. For in that sonorous soul everything took shape in sound. It sang of light. It sang of darkness, sang of life and death. It sang for those who were victorious in battle. It sang for himself who was conquered and laid low. It sang. All was song. It was nothing but song.

Source: Alexander’s Feast http://www.bartleby.com/40/265.html (1697), l. 50–51.

The Third Sacred School, Volume 2, Chapter 73
As of a Trumpet, On Eagle's Wings, The Third Sacred School

Published version, in the Atlantic Monthly (February 1862)
He has sounded out the trumpet that shall never call retreat,
He has waked the earth's dull sorrow with a high ecstatic beat...
First manuscript version (19 November 1861).
The Battle Hymn of the Republic (1861)
Context: He has sounded forth the trumpet that shall never call retreat;
He is sifting out the hearts of men before His judgment-seat.
Oh! be swift my soul to answer him, be jubilant my feet!
Our God is marching on.

Variant translation: Let the trumpet of the day of judgment sound when it will, I shall appear with this book in my hand before the Sovereign Judge, and cry with a loud voice, This is my work, there were my thoughts, and thus was I. I have freely told both the good and the bad, have hid nothing wicked, added nothing good.
Confessions of Jean-Jacques Rousseau (1765-1770; published 1782), Book I
Context: Whenever the last trumpet shall sound, I will present myself before the sovereign judge with this book in my hand, and loudly proclaim, thus have I acted; these were my thoughts; such was I. With equal freedom and veracity have I related what was laudable or wicked, I have concealed no crimes, added no virtues; and if I have sometimes introduced superfluous ornament, it was merely to occupy a void occasioned by defect of memory: I may have supposed that certain, which I only knew to be probable, but have never asserted as truth, a conscious falsehood. Such as I was, I have declared myself; sometimes vile and despicable, at others, virtuous, generous and sublime; even as thou hast read my inmost soul: Power eternal! assemble round thy throne an innumerable throng of my fellow-mortals, let them listen to my confessions, let them blush at my depravity, let them tremble at my sufferings; let each in his turn expose with equal sincerity the failings, the wanderings of his heart, and, if he dare, aver, I was better than that man.

Grand Chorus.
A Song for St. Cecilia's Day http://www.englishverse.com/poems/a_song_for_st_cecilias_day_1687 (1687)
Source: The Major Works
Context: So, when the last and dreadful Hour
This crumbling Pageant shall devour,
The trumpet shall be heard on high,
The dead shall live, the living die,
And musick shall untune the Sky.

Love is Enough (1872), Song VI: Cherish Life that Abideth
Context: Live on, for Love liveth, and earth shall be shaken
By the wind of his wings on the triumphing morning,
When the dead, and their deeds that die not shall awaken,
And the world's tale shall sound in your trumpet of warning,
And the sun smite the banner called Scorn of the Scorning,
And dead pain ye shall trample, dead fruitless desire,
As ye wend to pluck out the new world from the fire.

Part II, Ch. XIII <!-- Sect. 4 -->
The Pilgrim's Progress (1678), Part II
Context: Then Mr. Honest called for his friends, and said unto them, I die, but shall make no will. As for my honesty, it shall go with me; let him that comes after be told of this. When the day that he was to be gone was come, he addressed himself to go over the river. Now the river at that time over-flowed its banks in some places; but Mr. Honest, in his lifetime, had spoken to one Good-conscience to meet him there, the which he also did, and lent him his hand, and so helped him over. The last words of Mr. Honest were, Grace reigns! So he left the world.After this it was noised abroad that Mr. Valiant-for-truth was taken with a summons by the same post as the other, and had this for a token that the summons was true, "That his pitcher was broken at the fountain." When he understood it, he called for his friends, and told them of it. Then said he, I am going to my Father’s; and though with great difficulty I have got hither, yet now I do not repent me of all the trouble I have been at to arrive where I am. My sword I give to him that shall succeed me in my pilgrimage, and my courage and skill to him that can get it. My marks and scars I carry with me, to be a witness for me that I have fought His battles who will now be my rewarder. When the day that he must go hence was come, many accompanied him to the river-side, into which as he went, he said, "Death, where is thy sting?" And as he went down deeper, he said, "Grave, where is thy victory?"
So he passed over, and all the trumpets sounded for him on the other side.

View ascribed by Smith to his friend Henry Luttrell; reported in Hesketh Pearson, The Smith of Smiths (London: Hamish Hamilton, 1934), p. 236