20. 3. A man may be doing good, which he believes to be of charity, and all the while not be shunning evil; and yet every evil is contrary to charity.
It is evident that to shun evil [and to do Christian good] are two distinct things; for there are people who do every good of charity from piety and from thinking about eternal life, and all the while they do not know that hating, bearing revenge, committing whoredom, plundering and injuring, slandering, and so bearing false witness, and many [other things, are to be shunned]. There are judges who live piously, and yet do not count it a sin to make their judgments on a basis of friendship, relationship, or with a view to honour and gain; and even if they do know they are evils, they confirm themselves in the belief that they are not. So also do others. In a word, there are two distinct things, shunning evils as sins, and doing Christian good. He who shuns evils as sins does Christian goods, but they who do good and do not shun evils as sins, do not do any Christian good; for evil is contrary to charity, and is therefore to be abolished first before the good which anyone does is accompanied with charity, that is, is of charity. No one is able to do good and at the same time to do evil, or to will good and also evil.