6 “Who keeps truth for ever.” What “truth for ever”? What “truth” does He “keep,” and wherein does “He keep it for ever”? “Who executes judgment for them that suffer wrong”. He avenges them that suffer wrong. There comes at once to you the voice of the Apostle: “now therefore there is altogether a fault among you, that you go to law one with another: why do ye not rather suffer wrong?” He urged you not to suffer annoyance, but to suffer wrong: for not every annoyance is wrong.
For whatever you suffer lawfully is not a wrong; lest perchance you should say, I also am among those who have suffered wrong, for I have suffered such a thing in such a place, and such a thing for such a reason. Consider whether you have suffered a wrong. Robbers suffer many things, but they suffer no wrong. Wicked men, evil doers, house-breakers, adulterers, seducers, all these suffer many evils, yet is there no wrong. It is one thing to suffer wrong; it is another to suffer tribulation, or penalty, or annoyance, or punishment.
Consider where you are; see what you have done; see why you are suffering; and then you see what you are suffering. Right and wrong are contraries. Right is what is just. For not all that is called right, is right. What if a man lay down for you unjust right? Nor indeed is it to be called right, if it is unjust. That is true right, which is also just. Consider what you have done, not what you are suffering. If you have done right, you are suffering wrong; if you have done wrong, you are suffering right....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)