“One will rarely err if extreme actions be ascribed to vanity, ordinary actions to habit, and mean actions to fear.”

Source: The 7 Habits of Highly Effective People

Source: A Dictionary of Thoughts, 1891, pp. 114-115.

"Partaking in Other Men's Sins", an address at St. Margaret's Church, Lothbury, England (12 June 1855), printed in Golden Lectures (1855); eventually part of this statement become paraphrased in several slight variations, and has usually been misattributed to Herman Melville, i.e.: "We cannot live only for ourselves. A thousand fibers connect us with our fellow men; and along these fibers, as sympathetic threads, our actions run as causes, and they come back to us as effects".
Context: There is not one of you whose actions do not operate on the actions of others — operate, we mean, in the way of example. He would be insignificant who could only destroy his own soul; but you are all, alas! of importance enough to help also to destroy the souls of others.... Ye cannot live for yourselves; a thousand fibres connect you with your fellow-men, and along those fibres, as along sympathetic threads, run your actions as causes, and return to you as effects.

Source: The Final Empire

The Westminster Review, vol. 6 (1826), p. 13
Context: This habit of forming opinions, and acting upon them without evidence, is one of the most immoral habits of the mind.... As our opinions are the fathers of our actions, to be indifferent about the evidence of our opinions is to be indifferent about the consequences of our actions. But the consequences of our actions are the good and evil of our fellow-creatures. The habit of the neglect of evidence, therefore, is the habit of disregarding the good and evil of our fellow-creatures.

Original: (it) Non trasformare i tuoi pensieri in paure. Trasforma i tuoi sogni in azioni e le tue azioni in successi.
Source: prevale.net

The Table Talk of Samuel Marchbanks (1949)

How the Semblances of Things are to be combated, Chap. xviii.
Bartlett's Familiar Quotations, 10th ed. (1919)