Otto von Bismarck: Use

“Europe today is a powder keg and the leaders are like men smoking in an arsenal … A single spark will set off an explosion that will consume us all … I cannot tell you when that explosion will occur, but I can tell you where … Some damned foolish thing in the Balkans will set it off.”

Otto von Bismarck

No record of this quotation appears to exist in German.
In The World Crisis, Vol I: 1911-1914 https://books.google.com/books?id=6l6Fgnz8fXIC&lpg=PP1&pg=PA96#v=onepage&q&f=false (originally published in 1923), Winston Churchill asserted that during the July Crisis, German shipping magnate and diplomat Albert Ballin told him that Bismarck had said to him, "that one day the great European War would come out of some damned foolish thing in the Balkans" a year before his death.
The full quote above appears in "European Diary" by Andrei Navrozov, in Chronicles Vol. 32 (2008) as a comment during the Congress of Berlin in 1878. "European Diary" is a series of excerpts from Navrozov's unpublished (as of 2017) novel in English, Earthly Love: A Day in the Life of a Hypocrite.
Disputed

Men

“We Germans fear God, but nothing else in the world; and it is the fear of God, which lets us love and foster peace.”

Otto von Bismarck

Wir Deutsche fürchten Gott, aber sonst nichts in der Welt - und die Gottesfurcht ist es schon, die uns den Frieden lieben und pflegen lässt.
Speech to the Reichstag (6 February 1888) reichstagsprotokolle.de 1887/88,2 http://www.reichstagsprotokolle.de/Blatt3_k7_bsb00018648_00043.html p. 733 (D)
1880s

Love , God , World , Fear

“My dear Professor, a war would have cost us at least 30,000 brave soldiers, and at best we should have gained nothing by it. Besides, anyone who has once looked into the glassy eyes of a dying warrior on the battle-field would think twice before beginning a war.”

Otto von Bismarck

Mein lieber Professor, ein solcher Krieg hätte uns wenigstens 30,000 Mann brave Soldaten gekostet, und uns im besten Falle keinen Gewinn gebracht. Wer aber nur ein Mal in das brechende Auge eines sterbenden Kriegers auf dem Schlachtfeld geblickt hat, der besinnt sich, bevor er einen Krieg anfängt.
In June 1867, protecting the Treaty of London
1860s

War , Thinking

“Let us lift Germany, so to speak, into the saddle. Surely when that is achieved, it will succeed at riding as well.”

Otto von Bismarck

Setzen wir Deutschland, so zu sagen, in den Sattel! Reiten wird es schon können.
Speech to Parliament of Confederation (1867)
1860s

“In the development of our tariff I am determined to oppose any modification in the direction of Free Trade, and to use my influence in favour of greater protection and of a higher revenue from frontier duties.”

Otto von Bismarck

Speech to the Reichstag (28 March 1881), quoted in W. H. Dawson, Bismarck and State Socialism: An Exposition of the Social and Economic Legislation of Germany since 1870 (London: Swan Sonnenschein & Co., 1891), p. 54
1880s