To him which smote great kings - On this passage see the notes at Psalm 135:10-12. There is little difference in the two places, except that here the statement is divided by the refrain, "For his mercy endureth forever." The idea in the whole passage, in view of the divine interposition in slaying the mighty kings, and in giving their land for a possession to the Hebrew people, is, that it was a proof of mercy and benevolence. It is benevolence to mankind and to the church of God - it is in the interests of humanity, of domestic peace, and of the charities of life, to remove wicked people from the world. This mercy may be manifested further, not merely in removing the wicked, but in transferring their possessions to those who will make a better use of them. Thus the possessions of these mighty kings, Sihon and Og, were transferred to the people of God, and lands which had been devoted to the service of blood, ambition, crime, pollution, and idolatry, became devoted to the service of religion and righteousness. In like manner, through the removal of a wicked man from the world by death, God may cause his wealth, accumulated by avarice and dishonesty, to be transferred to the hands of children who will make a good use of it - children converted as if in anticipation of this, and with a view to this. Among the highest expressions of mercy to the world may be, therefore, the removal of wicked princes in war - or the removal of wicked people, in other ranks of life, by death in any form.

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.