Ante-Nicene Fathers, Vol VIII:
Pseudo-Clementine Literature.: Chapter III

Chapter III.—Righteous Anger.

“And all the more eagerly must we strive on this account, that while there is time, the collected vices of evil custom may be cut off.  And this you shall not be able to do otherwise, than by being angry with yourselves on account of your profitless and base doings.  For this is righteous and necessary anger, by which every one is indignant with himself, and accuses himself for those things in which he has erred and done amiss; and by this indignation a certain fire is kindled in us, which, applied as it were to a barren field, consumes and burns up the roots of vile pleasure, and renders the soil of the heart more fertile for the good seed of the word of God.  And I think that you have sufficiently worthy causes of anger, from which that most righteous fire may be kindled, if you consider into what errors the evil of ignorance has drawn you, and how it has caused you to fall and rush headlong into sin, from what good things it has withdrawn you, and into what evils it has driven you, and, what is of more importance than all the rest, how it has made you liable to eternal punishments in the world to come.  Is not the fire of most righteous indignation kindled within you for all these things, now that the light of truth has shone upon you; and does not the flame of that anger which is pleasing to God rise within you, that every sprout may be burnt up and destroyed from the root, if haply any shoot of evil concupiscence has budded within you?