Charles H. Spurgeon on Psalms 135:10

Who smote great nations, and slew mighty kings. The nations of Canaan joined in the desperate resistance offered by their monarchs, and so they were smitten; while their kings, the ringleaders of the fight, were slain. Those who resist the divine purpose will find it hard to kick against the pricks. The greatness of the nations and the might of the kings availed nothing against the Lord. He is prepared to mete out vengeance to those who oppose his designs: those who dream of him as too tender to come to blows have mistaken the God of Israel. He intended to bless the world through his chosen people, and he would not be turned from his purpose: cost what it might, he would preserve the candle of truth which he had lighted, even though the blood of nations should be spilt in its defence. The wars against the Canaanite races were a price paid for the setting up of a nation which was to preserve for the whole world the lively oracles of God.