“I speak perhaps, with a warmth of indignation unbefitting a Foreign Secretary, but with the news of this outrage...I confess that I find it difficult to measure my epithets, for...this Irish packet boat, crammed as it always is with men, women, and children, in broad daylight was deliberately torpedoed by a German submarine. It was carrying no military stores. It was serving no military ends. It was pure barbarism, pure frightfulness, deliberately carried out. ... I cannot measure the wicked folly of the proceeding of which they have been guilty. ... I wish I could think that these atrocious crimes were the crimes of a small dominant military caste. I agree that the direction of policy, the direction of national policy, may be in the hands of a small caste, but it is incredible that crimes like these, perpetrated in the light of day, known to all mankind, condemned from one end of the civilized world to the other, should go on being repeated month after month of four years of embittered warfare if it did not commend itself to the population which commits them.”

Don’t leave Syria to become a graveyard — this generation’s responsibility to the world (13 October 2015)

The Never-Ending Wrong (1977)

A Soldier's Declaration (July 1917)
Context: I am making this statement as an act of wilful defiance of military authority, because I believe that the War is being deliberately prolonged by those who have the power to end it.
I am a soldier, convinced that I am acting on behalf of soldiers. I believe that this War, on which I entered as a war of defence and liberation, has now become a war of aggression and conquest.

Hannity & Colmes (5 May 2004).
2004
Context: I think the other point that no one is making about the abuse photos is just the disproportionate number of women involved, including a girl general running the entire operation. I mean, this is lesson, you know, number 1,000,047 on why women shouldn't be in the military. In addition to not being able to carry even a medium-sized backpack, women are too vicious.

Charles V may have said something in this general format, but not with this specific wording. Variants have been quoted for centuries, and the earliest known citation, itself a secondary source dating from 40 years after his death, gives two versions that both differ from the modern one. Girolamo Fabrizi d'Acquapendente's 1601 De Locutione gives:

Unde solebat, ut audio, Carolus V Imperator dicere, Germanorum linguam esse militarem: Hispanorum amatoriam: Italorum oratoriam: Gallorum nobilem ("When Emperor Charles V used to say, as I hear, that the language of the Germans was military; that of the Spaniards pertained to love; that of the Italians to prayer; that of the French was noble").

Alius vero, qui Germanus erat, retulit, eundem Carolum Quintum dicere aliquando solitum esse; Si loqui cum Deo oporteret, se Hispanice locuturum, quod lingua Hispanorum gravitatem maiestatemque prae se ferat; si cum amicis, Italice, quod Italorum dialectus familiaris sit; si cui blandiendum esset, Gallice, quod illorum lingua nihil blandius; si cui minandum aut asperius loquendum, Germanice, quod tota eorum lingua minax, aspera sit ac vehemens (Indeed another, who was German, related that the same Charles V sometimes used to say: if it was necessary to talk with God, that he would talk in Spanish, which language suggests itself for the graveness and majesty of the Spaniards; if with friends, in Italian, for the dialect of the Italians was one of familiarity; if to caress someone, in French, for no language is tenderer than theirs; if to threaten someone or to speak harshly to them, in German, for their entire language is threatening, rough and vehement").

As quoted by Haing S. Ngor (1987) Surviving the Killing Fields, pages 46-47.
Speeches

"Pierre Menard, Author of the Quixote" ["Pierre Menard, autor del Quijote"]
The Garden of Forking Paths (1942)

Source: The Drunkard's Walk, Chapter 7, Measurement And The Law Of Errors, p. 129

2012, Yangon University Speech (November 2012)
Context: And to protect the freedom of all the voters, those in power must accept constraints. That's what our American system is designed to do. Now, America may have the strongest military in the world, but it must submit to civilian control. I, as the President of the United States, make determinations that the military then carries out, not the other way around. As President and Commander-In-Chief, I have that responsibility because I'm accountable to the people.