When Israel crossed into the promised land, she entered from the south which, from the perspective of the southern kings, put them all in danger. The alliance of the Gibeonites with Israel gave Israel a strategic advantage. Gibeon was a large, well fortified city with a well trained army. They would now fight for Israel. Additionally, it was in the highlands, which gave Israel the advantage of high ground (along with Ai).
Five southern kings (probably the most powerful) created a coalition of opposition and challenged Israel. But Israel defeated them and the courage they received from that defeat (which Joshua used skillfully) helped them to go on and defeat seven more kings and their cities. And so it was that Israel took the southern part of the promised land.
The question everyone wants answered is: “How could the sun stand still?” The sun doesn’t move.
Though the sun itself doesn’t move, it appears to move across the sky from east to west. With the lengthening of the day, the son would appear to stand still. It all adds to the drama of the story – which it is intended to do. The writer of Joshua notes there has never been a day nor a time, at least up to his own day, when God listened to and answered a prayer like he did that day for Joshua. This is the possibility for God’s people. There is nothing God cannot do for them, if they will but take their requests to God.
What about the destruction of the Canaanites? Joshua “subdued the whole region,” “he left no survivors,” “he totally destroyed all who breathed.” How could God countenance such behavior?
It was, of course, God’s command and becomes an important lesson. The Canaanites were not destroyed just to get their land. They were destroyed because they were evil. God had given them hundreds of years to repent, but they had not, and He knew they would not. He had bided His time long enough. If you think eternal punishment beneath the dignity of a merciful God, you should consider the point made in Joshua chapter ten again. Justice demands punishment for sin, and God will not let it go.