Albert Barnes Commentary 1 Kings 20:42

"And he said unto him, Thus saith Jehovah, Because thou hast let go out of thy hand the man whom I had devoted to destruction, therefore thy life shall go for his life, and thy people for his people." — 1 Kings 20:42 (ASV)

A man whom I appointed to utter destruction - or to חרם chērem, that is, a man on whom My curse had been laid (Leviticus 27:28).