4 And the Lord shall do unto them. He promises that, when they shall come into the land of Canaan, they shall be conquerors of all its nations: and this he confirms by experience; for, as God had delivered Sihon king of the Arnorites, and Og king of Bashan, into their hands, so also He would give them the same success in subduing their other enemies. The world is indeed subject to many revolutions, but God still remains like Himself, not only because His counsel is never changed, but because His power is never diminished. By a real proof, therefore, as it is called, he encourages the expectations of the people, and at the same time exhorts them resolutely to execute God’s command, viz., that they should purge the land of Canaan by the destruction of all its inhabitants. In appearance, indeed, this was fierce and cruel, to leave not even one alive; but, since God had justly devoted them to extinction, it was not lawful for the Israelites to inquire what was to be done, but to abandon all discussion, and to obey God’s command. In that they spared many, so much the worse was their remissness, since God had often prepared them to execute the vengeance which He had decreed.