So the hearts and minds of kings are [a]unsearchable.
Proverbs 25:3 The ancient rabbis explained this as a reference to the countless details of government that are a king's responsibility.
Proverbs 25:22 This expression may refer to an Egyptian custom in which a penitent man carried a pan of coals on his head as a sign of repentance. The message of these verses is the admonition to return good for evil in the hope that your enemy will be moved to repentance.