Charles Ellicott Commentary Proverbs 17:9

"He that covereth a transgression seeketh love; But he that harpeth on a matter separateth chief friends." — Proverbs 17:9 (ASV)

He that covereth a transgression seeketh love — that is, one who does not notice, but rather conceals and excuses, anything done against him; that man follows after charity (1 Corinthians 14:1). (Compare to Proverbs 10:12.)

He that repeateth a matter, who is always returning to old grievances, alienates (even his) chief friend.