Antonius Melissa, Book. II. Sermon 69.1
Never be afraid of the slanderer who addresses you. But rather say, Stop, brother; I daily commit more grievous errors, and how can I judge him? For you will gain two things, healing with one plaster both yourself and your neighbour. He shows what is really evil. Whence, by these arguments, God has contrived to make each one's disposition manifest.
It is not abstaining from deeds that justifies the believer, but purity and sincerity of thoughts.