Charles Ellicott Commentary Proverbs 20:30

"Stripes that wound cleanse away evil; And strokes [reach] the innermost parts." — Proverbs 20:30 (ASV)

The blueness of a wound. —Rather, the stripes of a wound, or wounds which cut into the flesh, cleanse away evil.

So do stripes the inward parts of the belly.— Better, and blows (which reach) the inward parts of the belly, i.e., which are felt in the inmost recesses of the heart . Kindness is thrown away upon some people: they can only be touched by punishment.