The mourning for which [Jesus] promises eternal consolation, dearly beloved, has nothing to do with ordinary worldly distress; for the tears which have their origin in the sorrow common to all humanity do not make anyone blessed. There is another cause for the sighs of the saints, another reason for their blessed tears. Religious grief mourns for sin, one’s own or another’s; it does not lament because of what happens as a result of God’s justice, but because of what is done by human malice. Indeed, those who do wrong are more to be lamented than those who suffer it, for their wickedness plunges the sinner into punishment, whereas endurance can raise the just to glory.

—Sermon 95.4-6

I recently wrote a piece about Muslim terrorists in which I said I prayed for them every day. The above excerpt from Leo is why I can do that (besides, of course, that our Lord commands us to do so).