Cursed be he that doeth the work of the LORD deceitfully, and cursed be he that keepeth back his sword from blood.
Cursed be he that doeth the work of the Lord - the divinely appointed utter devastation of Moab.
Negligently. To represent how entirely this is God's will, a curse is pronounced on the Chaldeans, the instrument, if they do it negligently (margin), or by halves (Judges 5:23): cf. Saul's sin as to Amalek (1 Samuel 15:3; 1 Samuel 15:9), and Ahab's as to Syria (1 Kings 20:42).