“When he is most powerful, nothing does he become.”

As quoted in A Year with the Saints (1891) by Anonymous, p. 47

Source: East of Eden

Source: 2000s, Letter to a Christian Nation (2006), p. 55

Alex Ferguson, manager of Manchester United FC ( Source http://news.bbc.co.uk/sport1/hi/football/teams/l/liverpool/4647845.stm)

"On the Uses of a Landed Gentry" address in Edinburgh (6 November 1876), published in Short Studies on Great Subjects, Vol. III (1893), p. 406
Context: The landlord may become a direct oppressor. He may care nothing for the people, and have no object but to squeeze the most that he can out of them fairly or unfairly. The Russian government has been called despotism tempered with assassination. In Ireland landlordism was tempered by assassination.
Unfortunately the wrong man was generally assassinated. The true criminal was an absentee, and his agent was shot instead of him. A noble lord living in England, two of whose agents had lost their lives already in his service, ordered the next to post a notice in his Barony that he intended to persevere in what he was doing, and if the tenants thought they would intimidate him by shooting his agents, they would find themselves mistaken.

Aphorism 146 from Jenseits von Gut und Böse (Beyond Good and Evil) an 1886 book by the German philosopher Friedrich Nietzsche.

Translated from: Wer mit Ungeheuern kämpft, mag zusehn, dass er nicht dabei zum Ungeheuer wird. Und wenn du lange in einen Abgrund blickst, blickt der Abgrund auch in dich hinein.

Source: Gutenberg-DE

Translation source: Hollingdale
Misattributed

Muhammad Kulayni, Usūl al-Kāfī, vol.2, p. 234