My own personal collection of 'good quotes' are almost all military-related, because that's the subject I write on and where I use them. I have never particularly worried about the source of a quote, as long as I can verify that source in some way as specifically as I can - and sometimes, as when a quote is attributed to a 'proverb' to use it all I can legitimately do is make sure the attribution is identified as an anonymous original and therefore automatically suspect.
For examples:
On the quality of troops:
"It is not the big armies that win battles, it is the good ones".
- Maurice de Saxe, Reveries, 1732 CE
On Decisiveness:
"The God of War hates those who hesitate"
-Euripedes, Herclidae, 425 BCE
On Training:
"To lead an untrained people to war is to throw them away."
-Kong-fu-Tse, Analects, 500 BCE
On Artillery:
"The nimble gunner
With linstock now the devilish cannon touches,
And all goes down before him."
-William Shakespeare, King Henry V, Act III, 1598 CE
On Conscription:
"Any blockhead is good enough to be shot at."
-English proverb, 18th century CE
On Defensive Weapons:
"A weapon is offensive or defensive depending on which end of it is pointing at you."
- Aristide Brand (attributed) 1930 CE