For indeed a wise man cannot in a moment of time change from absolute badness to perfect goodness, and suddenly abandon for ever all that vice, of which he could not during a long period of time divest himself of any portion.
 Plutarch, Moralia (c. 100 AD). copy citation

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Author Plutarch
Source Moralia
Topic goodness vice
Date c. 100 AD
Language English
Reference
Note Translated by Arthur Richard Shilleto
Weblink http://www.gutenberg.org/files/23639/23639-h/23639-h.htm

Context

“But just as in these cases there is no improvement unless, by the abatement of what weighs them down till they rise in the opposite scale, they recognize a change, so in the case of those who profess philosophy no improvement or sign of improvement can be supposed, unless the soul lay aside and purge itself of some of its imperfection, and if it continue altogether bad until it become absolutely good and perfect. For indeed a wise man cannot in a moment of time change from absolute badness to perfect goodness, and suddenly abandon for ever all that vice, of which he could not during a long period of time divest himself of any portion. And yet you know, of course, that those who maintain these views frequently give themselves much trouble and bewilderment about the difficulty, that a wise man does not perceive that he has become wise, but is ignorant and doubtful that in a long period of time by little and little, by removing some things and adding others, there will be a secret and quiet improvement, and as it were passage to virtue.” source