C. F. Keil and Franz Delitzsch on Proverbs 31:12

Pro 31:12 12 ג She doeth good to him, and not evil,        All the days of her life; or, as Luther translates:

“Sie thut jm liebs und kein leids.” [She does him good, and no harm.]

She is far from ever doing him evil, she does him only good all her life long; her love is not dependent on freaks, it rests on deep moral grounds, and hence derives its power and purity, which remain ever the same. גּמל signifies to accomplish, to perform. To the not assimilated form גּמלתהוּ, cf. יסּרתּוּ, 1b.