“I admire the wisdom of the Creator, which manifests itself in so many various modes, and demonstrate it to others.”

1930s, Wisehart interview (1930)
Context: I do not believe in a God who maliciously or arbitrarily interferes in the personal affairs of mankind. My religion consists of an humble admiration for the vast power which manifests itself in that small part of the universe which our poor, weak minds can grasp!

Source: A New Concept of the Universe (1953), p. 139

Kulturphilosophie (1923), Vol. 2 : Civilization and Ethics
Context: Affirmation of the world, which means affirmation of the will-to-live that manifests itself around me, is only possible if I devote myself to other life. From an inner necessity, I exert myself in producing values and practising ethics in the world and on the world even though I do not understand the meaning of the world. For in world- and life-affirmation and in ethics I carry out the will of the universal will-to-live which reveals itself in me. I live my life in God, in the mysterious divine personality which I do not know as such in the world, but only experience as mysterious Will within myself.
Rational thinking which is free from assumptions ends therefore in mysticism. To relate oneself in the spirit of reverence for life to the multiform manifestations of the will-to-live which together constitute the world is ethical mysticism. All profound world-view is mysticism, the essence of which is just this: that out of my unsophisticated and naïve existence in the world there comes, as a result of thought about self and the world, spiritual self-devotion to the mysterious infinite Will which is continuously manifested in the universe.

1930s, Wisehart interview (1930)

Source: Reason: The Only Oracle Of Man (1784), Ch. V Section II - Containing Observations on the Providence and Agency of God, as it Respects the Natural and Moral World, with Strictures on Revelation in General
Context: The idea of a God we infer from our experimental dependence on something superior to ourselves in wisdom, power and goodness, which we call God; our senses discover to us the works of God which we call nature, and which is a manifest demonstration of his invisible essence. Thus it is from the works of nature that we deduce the knowledge of a God, and not because we have, or can have any immediate knowledge of, or revelation from him.

Under Fire (1916), Ch. 24 - The Dawn
Context: There are all those things against you. Against you and your great common interests which as you dimly saw are the same thing in effect as justice, there are not only the sword-wavers, the profiteers, and the intriguers.
There is not only the prodigious opposition of interested parties — financiers, speculators great and small, armorplated in their banks and houses, who live on war and live in peace during war, with their brows stubbornly set upon a secret doctrine and their faces shut up like safes.
There are those who admire the exchange of flashing blows, who hail like women the bright colors of uniforms; those whom military music and the martial ballads poured upon the public intoxicate as with brandy; the dizzy-brained, the feeble-minded, the superstitious, the savages.
There are those who bury themselves in the past, on whose lips are the sayings only of bygone days, the traditionalists for whom an injustice has legal force because it is perpetuated, who aspire to be guided by the dead, who strive to subordinate progress and the future and all their palpitating passion to the realm of ghosts and nursery-tales.
With them are all the parsons, who seek to excite you and to lull you to sleep with the morphine of their Paradise, so that nothing may change. There are the lawyers, the economists, the historians — and how many more? — who befog you with the rigmarole of theory, who declare the inter-antagonism of nationalities at a time when the only unity possessed by each nation of to-day is in the arbitrary map-made lines of her frontiers, while she is inhabited by an artificial amalgam of races; there are the worm-eaten genealogists, who forge for the ambitious of conquest and plunder false certificates of philosophy and imaginary titles of nobility. The infirmity of human intelligence is short sight. In too many cases, the wiseacres are dunces of a sort, who lose sight of the simplicity of things, and stifle and obscure it with formulae and trivialities. It is the small things that one learns from books, not the great ones.
And even while they are saying that they do not wish for war they are doing all they can to perpetuate it. They nourish national vanity and the love of supremacy by force. "We alone," they say, each behind his shelter, "we alone are the guardians of courage and loyalty, of ability and good taste!" Out of the greatness and richness of a country they make something like a consuming disease. Out of patriotism — which can be respected as long as it remains in the domain of sentiment and art on exactly the same footing as the sense of family and local pride, all equally sacred — out of patriotism they make a Utopian and impracticable idea, unbalancing the world, a sort of cancer which drains all the living force, spreads everywhere and crushes life, a contagious cancer which culminates either in the crash of war or in the exhaustion and suffocation of armed peace.
They pervert the most admirable of moral principles. How many are the crimes of which they have made virtues merely by dowering them with the word "national"? They distort even truth itself. For the truth which is eternally the same they substitute each their national truth. So many nations, so many truths; and thus they falsify and twist the truth.
Those are your enemies. All those people whose childish and odiously ridiculous disputes you hear snarling above you — "It wasn't me that began, it was you!" — "No, it wasn't me, it was you!" — "Hit me then!" — "No, you hit me!" — those puerilities that perpetuate the world's huge wound, for the disputants are not the people truly concerned, but quite the contrary, nor do they desire to have done with it; all those people who cannot or will not make peace on earth; all those who for one reason or another cling to the ancient state of things and find or invent excuses for it — they are your enemies!
They are your enemies as much as those German soldiers are to-day who are prostrate here between you in the mud, who are only poor dupes hatefully deceived and brutalized, domestic beasts. They are your enemies, wherever they were born, however they pronounce their names, whatever the language in which they lie. Look at them, in the heaven and on the earth. Look at them, everywhere! Identify them once for all, and be mindful for ever!

Preface, translation in William Whewell's History of the Inductive Sciences http://books.google.com/books?id=vlQEAAAAQAAJ (1837)
Philosophiae Naturalis Principia Mathematica (1687)

Variant: Such a simple concept, yet so true: that which we manifest is before us; we are the creators of our own destiny. Be it through intention or ignorance, our successes and our failures have been brought on by none other than ourselves.
Source: The Art of Racing in the Rain