Further, whenever a man sins through certain malice, his will must needs be inclined of itself to the evil he chooses.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic evil sin
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17897/pg17897-images.html

Context

“But the greatest fall seems to be that of the man who sins through certain malice. Therefore a man comes to sin through certain malice, not from the outset, but from inveterate custom, which may engender a habit. Obj. 3: Further, whenever a man sins through certain malice, his will must needs be inclined of itself to the evil he chooses. But by the nature of that power man is inclined, not to evil but to good. Therefore if he chooses evil, this must be due to something supervening, which is passion or habit. Now when a man sins through passion, he sins not through certain malice, but through weakness, as stated” source