Sourced

• I think it better to keep a profound silence with regard to the Christian fables, which are canonized by their antiquity and the credulity of absurd and insipid people.
  • Letters of Voltaire and Frederick the Great (New York: Brentano's, 1927), trans. Richard Aldington, letter 37 from Frederick to Voltaire (June 1738)

• A single Voltaire will do more honor to France than a thousand pedants, a thousand false wits, a thousand great men of inferior order.
  • Letters of Voltaire and Frederick the Great (New York: Brentano's, 1927), trans. Richard Aldington, letter 48 from Frederick to Voltaire (1740-01-06)

• Alle Religionen sind gleich und gut, wenn nur die Leute, die sie praktizeren, ehrliche Leute sind; und wenn Türken und Heiden kämen und wollten das Lande pöpulieren, so wollen wir ihnen Moscheen und Kirchen bauen.
  • All Religions are equal and good, if only the people that practice them are honest people; and if Turks and heathens came and wanted to live here in this country, we would build them mosques and churches.
  • 1740 note on a question whether a Catholic was allowed the citizenship of a Prussian city.

• Avec toute l’algèbre du monde on n’est souvent qu’un sot lorsqu’on ne sait pas autre chose. Peut-être dans dix ans la société tirera-t-elle de l’avantage des courbes que des songe-creux d’algébristes auront carrées laborieusement. J’en félicite d’avance la postérité; mais, à vous parler vrai, je ne vois dans tous ces calculs qu’une scientifique extravagance. Tout ce qui n’est ni utile ni agréable ne vaut rien. Quant aux choses utiles, elles sont toutes trouvées; et, pour les agréables, j’espère que le bon goût n’y admettra point d’algèbre.
  • [A] man with all the algebra in the world is often only an ass when he knows nothing else. Perhaps in ten years society may derive advantage from the curves which these visionary algebraists will have laboriously squared. I congratulate posterity beforehand. But to tell you the truth I see nothing but a scientific extravagance in all these calculations. That which is neither useful nor agreeable is worthless. And as for useful things, they have all been discovered; and to those which are agreeable, I hope that good taste will not admit algebra among them.
  • Letters of Voltaire and Frederick the Great (New York: Brentano's, 1927), trans. Richard Aldington, letter 93 from Frederick to Voltaire (1749-05-16)

• Kerls, wollt ihr ewig leben?
  • Dogs, would you live forever?
  • Variation: Rogues, would you live forever? (Ihr Racke, wollen sie ewig leben?) http://www.websters-online-dictionary.org/wo/would.html
  • Variation: Rascals, Do you want to life forever? (Kerls, wollt ihr denn ewig leben?)
  • Addressing retreating Prussians at the Battle of Kolin (1757-06-18)

• Do you think I take any pleasure in this dog's life, in seeing and causing death in people unknown to me, in losing friends and acquaintances daily, in seeing my reputation ceaselessly exposed to the caprices of fortune, in spending the whole year with uneasiness and apprehension, in continually risking my life and my fortune? I certainly know the value of tranquility, the charms of society, the pleasures of life, and I like to be happy as much as anybody. Although I desire all these good things, I will not buy them with baseness and infamy. Philosophy teaches us to do our duty, to serve our country faithfully at the expense of our blood and of our repose, to commit our whole being to it.
  • Letters of Voltaire and Frederick the Great (New York: Brentano's, 1927), trans. Richard Aldington, letter 141 from Frederick to Voltaire (1759-07-02)

• Neither antiquity nor any other nation has imagined a more atrocious and blasphemous absurdity than that of eating God. — This is how Christians treat the autocrat of the universe.
  • Letters of Voltaire and Frederick the Great (New York: Brentano's, 1927), trans. Richard Aldington, letter 215 from Frederick to Voltaire (1776-03-19)

• It is disgusting to notice the increase in the quantity of coffee used by my subjects, and the amount of money that goes out of the country as a consequence. Everybody is using coffee; this must be prevented. His Majesty was brought up on beer, and so were both his ancestors and officers. Many battles have been fought and won by soldiers nourished on beer, and the King does not believe that coffee-drinking soldiers can be relied upon to endure hardships in case of another war.
  • 1777; quoted by Bert L. Vallée, Alcohol in the Western World, Scientific American, Vol. 278, No. 6 (June), 1998, pp. 80-85

• As to your Newton, I confess I do not understand his void and his gravity; I admit he has demonstrated the movement of the heavenly bodies with more exactitude than his forerunners; but you will admit it is an absurdity to maintain the existence of Nothing.
  • Letters of Voltaire and Frederick the Great (New York: Brentano's, 1927), trans. Richard Aldington, letter 221 from Frederick to Voltaire (1777-11-25)

• Je voulus faire un jet d’eau dans mon jardin; Euler calcula l’effort des roues pour faire monter l’eau dans un bassin, d’où elle devait retomber par des canaux, afin de jaillir à Sans-Souci. Mon moulin a été exécuté géométriquement, et il n’a pu élever une goutte d’eau à cinquante pas du bassin. Vanité des vanités! vanité de la géométrie!
  • I wanted to have a water jet in my garden: Euler calculated the force of the wheels necessary to raise the water to a reservoir, from where it should fall back through channels, finally spurting out in Sans Souci. My mill was carried out geometrically and could not raise a mouthful of water closer than fifty paces to the reservoir. Vanity of vanities! Vanity of geometry!
  • Letter H 7434 from Frederick to Voltaire (1778-01-25)

• It has been said by a certain general, that the first object in the establishment of an army ought to be making provision for the belly, that being the basis and foundation of all operations.

Unsourced

• A hat that let the rain in.
  • About his crown.

• Artillery adds dignity to what would otherwise be a vulgar brawl.

• Before I endorse this sentence, I am curious to hear of the measures you want to employ for making a simple soldier pay 2000 Taler.
  • Bevor ich das gegenwärtige Urteil bestätige, bin Ich doch neugierig, die Mittel zu wissen, deren man sich bedienen will, einen Soldaten 2000 Taler bezahlen zu lassen.
  • Note on a verdict against a soldier who was sentenced to a fine of 2000 thaler for smuggling.

• Diplomacy without power is like an orchestra without instruments.

• I am the first servant of my state.
  • Ich bin der erste Diener meines Staates.

• Religions must all be tolerated and the state has to keep an eye that none of them shall derogate the other, because here everyone must find his salvation in his own way.
  • Die Religionen müssen alle toleriert werden und der Fiscal muß nur das Auge darauf haben, dass Keine der Andern abruch tue, denn hier muß ein jeder nach seiner Fasson selig werden.
  • Reply on the question of his secretaries whether Catholic schools should be abolished in Protestant Prussia.

• That the arrested man has committed blasphemy is a proof that he does not know God. That he has slandered me, I pardon him. But for his insulting of an honorable member of the council, he shall be punished as an example and be sent to Spandau prison for half an hour.
  • Dass der Arrestat Gott gelästert hat, ist ein Beweis, dass er ihn nicht kennt. Daß er mich gelästert hat, vergebe ich ihm; daß er aber einen edlen Rat gelästert hat, dafür soll er exemplarisch bestraft werden und auf eine halbe Stunde nach Spandau kommen.
  • Answering a question by a mayor how to punish a man that had committed blasphemy and insulted the king and the City Council.

• The greatest and noblest pleasure which men can have in this world is to discover new truths; and the next is to shake off old prejudices.

• The monarch is a perpetual sentinel, who must watch... enemies of the state... it is not that he should remain the shadow of authority, but that he should fulfill [his] duties.

• The priest will stay. If he does not want to get up with the others on Judgement Day, he may well keep resting on his back.
  • Der Pfarrer bleibt. Wenn er am Jüngsten Tag nicht mit aufstehen will, kann er ruhig liegen bleiben.
  • Answer to the request of a parish in Pomerania to send a new priest, as the present one had ventured to deny the resurrection on Judgement Day.

Attributed

• Like a long boat which follows in the wake of the warship to which it is tied.
  • On the decline of the Dutch Republic subject to British power
  • Attributed in T. C. W. Blanning, The Eighteenth Century (Oxford, 2000)

• If my soldiers began to think, not one would remain in the ranks.
  • Attributed in J.A. Houlding, Fit for Service: The Training of the British Army, 1715-1795 (Oxford, 1981)

Misattributed

• Audacity, audacity, always audacity!
  • Il nous faut de l'audace, encore de l'audace, toujours de l'audace! http://www.gutenberg.org/dirs/etext04/8dscs10.txt
  • We must dare, dare again, always dare!
  • Georges Danton, speech, Assemblée legislative, Paris (1792-09-02), reported in Le Moniteur (1792-09-04)