C. F. Keil and Franz Delitzsch on Proverbs 12:21

Pro 12:21 21 No evil befalls the righteous,      But the godless are full of evil.

Hitzig translates און “sorrow,” and Zöckler “injury;” but the word signifies evil as ethical wickedness, and although it may be used of any misfortune in general (as in בּן־אוני, opp. בּנימין); thus it denotes especially such sorrow as is the harvest and product of sin, Pro 22:8; Job 4:8; Isa 59:4, or such as brings after it punishment, Hab 3:7; Jer 4:15. That it is also here thus meant the contrast makes evident. The godless are full of evil, for the moral evil which is their life-element brings out of itself all kinds of evil; on the contrary, no kind of evil, such as sin brings forth and produces, falls upon the righteous. God, as giving form to human fortune (Exo 21:13), remains in the background (cf. Psa 91:10 with Psa 5:1.); vid., regarding אנה, the weaker power of ענה, to go against, to meet, to march against, Fleischer, Levy’s Chald. Wörterbuch, 572.