“Morals excite passions, and produce or prevent actions. Reason of itself is utterly impotent in this particular. The rules of morality, therefore, are not conclusions of our reason.”

Source: On Aggression (1963), Ch. XII : On the Virtue of Scientific Humility
Context: Nobody can seriously believe that free will means that it is left entirely to the will of the individual, as to an irresponsible tyrant, to do or not do whatever he pleases. Our freest will underlies strict moral laws, and one of the reasons for our longing for freedom is to prevent our obeying other laws than these. It is significant that the anguished feeling of not being free is never evoked by the realisation that our behaviour is just as firmly bound to moral laws as physiological processes are to physical ones. We are all agreed that the greatest and most precious freedom of man is identical with the moral laws within him. Increasing knowledge of the natural causes of his own behaviour can certainly increase a man's faculties and enable him to put his free will into action, but it can never diminish his will. If, in the impossible case of an utopian complete and ultimate success of causal analysis, man should ever achieve complete insight into the causality of earthly phenomena, including the workings of his own organism, he would not cease to have a will but it would be in perfect harmony with the incontrovertible lawfulness of the universe, the Weltvernunft of the Logos. This idea is foreign only to our present-day western thought; it was quite familiar to ancient Indian philosophy and to the mystics of the middle ages.

" The Meat Eaters http://opinionator.blogs.nytimes.com/2010/09/19/the-meat-eaters/", The New York Times, 19 Sept. 2010

1830s, The Lyceum Address (1838)
Context: Passion has helped us; but can do so no more. It will in future be our enemy. Reason, cold, calculating, unimpassioned reason, must furnish all the materials for our future support and defence. — Let those materials be moulded into general intelligence, sound morality, and in particular, a reverence for the constitution and laws: and, that we improved to the last; that we remained free to the last; that we revered his name to the last; that, during his long sleep, we permitted no hostile foot to pass over or desecrate his resting place; shall be that which to learn the last trump shall awaken our WASHINGTON.
Upon these let the proud fabric of freedom rest, as the rock of its basis; and as truly as has been said of the only greater institution, "the gates of hell shall not prevail against it".

Book I, Ch. 3, sec. 4
An Essay Concerning Human Understanding (1689)

Source: Blood of the Fold

Es gibt kein äußeres Zeichen der Höflichkeit, das nicht einen tiefen sittlichen Grund hätte. Die rechte Erziehung wäre, welche dieses Zeichen und den Grund zugleich überlieferte.
Bk. II, Ch. 5, R. J. Hollingdale, trans. (1971), p. 195
Elective Affinities (1809)

On History.
1820s, Critical and Miscellaneous Essays (1827–1855)
Variant: What is all Knowledge too, but recorded Experience, and a product of History; of which, therefore, Reasoning and Belief, no less than Action and Passion, are essential materials.

Anarchism and Other Essays (1910), The Traffic in Women

Pt. VI, ch. III
Jude the Obscure (1895)