6 “How good is the God of Israel!” But to whom? “To men right in heart”. To men perverse what? Perverse He seems. So also in another Psalm He says: “With a holy man holy You shall be, and with the innocent man innocent You shall be, and with the perverse man perverse You shall be.” What is, perverse You shall be with the perverse man? Perverse the perverse man shall think You. Not that by any means God is made perverse. Far be it: what He is, He is. But in like manner as the sun appears mild to one having clear, sound, healthy, strong eyes, but against weak eyes does dart hard spears, so to say; the former looking at it it does invigorate, the latter it does torture, though not being itself changed, but the man being changed: so when you shall have begun to be perverse, and to you God shall seem to be perverse, you are changed, not He. That therefore to you will be punishment which to good men is joy. He calling to mind this thing, says, “How good is the God of Israel to men right in heart!”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)