quote:
"War is an ugly thing but not the ugliest of things; the decayed and degraded state of moral and patriotic feelings which thinks that nothing is worth war is much worse. A man who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself." John Stuart Mill
Great source, but rather long. What about ...
"God is a word to express, not our ideas, but the want of them."
-- John Stuart Mill, from Ira D. Cardiff, What Great Men Think of Religion, quoted from James A. Haught, ed., 2000 Years of Disbelief