To him which smote great kings
 Either the thirty one kings in the land of Canaan; or those who are after particularly mentioned; which seems best, since the kings of Canaan were petty kings, when these were greater ones; 
 for his mercy [endureth] for ever;
 the smiting of those kings were in mercy to Israel; both to preserve them from falling into their hands, and that they might possess their countries, as is later declared.