“False words are not only evil in themselves, but they infect the soul with evil.”
Phaedo 115e
literally: 'For know well', he said, 'o dearest Kriton, that to not speak well is not only sinful by itself, but lets evil intrude into the soul.'(εὖ γὰρ ἴσθι, ἦ δ᾽ ὅς, ὦ ἄριστε Κρίτων, τὸ μὴ καλῶς λέγειν οὐ μόνον εἰς αὐτὸ τοῦτο πλημμελές, ἀλλὰ καὶ κακόν τι ἐμποιεῖ ταῖς ψυχαῖς.)
Plato, Phaedo
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Socrates 168
classical Greek Athenian philosopher -470–-399 BCRelated quotes

“There is no evil in the atom, only in men's souls.”
Speech in Hartford, Connecticut (18 September 1952)

Dictata super Psalterium (Dictations on the Psalter). This is Luther's first major work from the years 1513 to 1515. (See What Luther Says, Ewald Martin Plass, ed., vol. 3, p. 1590. http://www.google.com/search?hl=en&lr=&tbs=bks%3A1&q=%22This+is+Luther%27s+first+major+work.+It+was+begun+in+the+summer+of+1513%22&btnG=Search&aq=f&aqi=&aql=&oq=&gs_rfai=)
Denifle, Heinrich, Luther and Lutherdom http://www.archive.org/details/cu31924029249567, p. 15; primary source: D. Martin Luthers Werke: kritische Gesamtausgabe, Weimar, Herman Bohlau, 1883, Vol. 3, p. 445. http://books.google.com/books?id=9YkVtSs8WdUC&pg=PA1&dq=%22Dictata+Super+Psalterium%22&hl=en&ei=Ms4qTJ3VGIe5nAewp8iqAQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCQQ6AEwADgK#v=onepage&q=%22Dictata%20Super%20Psalterium%22&f=false

Source: The Limits of Evolution, and Other Essays, Illustrating the Metaphysical Theory of Personal Ideaalism (1905), Appendix B: The System in its Ethical Necessity and its Practical Bearings, p.392

“It is not only spirits who punish the evil, the soul brings itself to judgment”
XIX. Why sinners are not punished at once.
On the Gods and the Cosmos
Context: It is not only spirits who punish the evil, the soul brings itself to judgment: and also it is not right for those who endure for ever to attain everything in a short time: and also, there is need of human virtue. If punishment followed instantly upon sin, men would act justly from fear and have no virtue.

As quoted in Epistulae morales ad Lucilium by Seneca, Epistle LXXXVII (trans. R. M. Gummere)

Source: The Tales of Alvin Maker, Seventh Son (1987), Chapter 10.
Source: Tomorrow, When the War Began

“There are no evils in Nature, there are only evils of Man.”
Title of manifesto (May 1990) http://www1.kunsthauswien.com/english/okologie.htm