Wow, this is a pretty heavy chapter. God lays out for the Israelites the plan to take over Canaan. There is talk of both destruction and driving nations out ahead of the Israelites with "the hornet." (vs 20) God does say that, when the Israelites have defeated a nation, they are to destroy everything associated with that nation's gods. "This is what you are to do to them: Break down their altars, smash their sacred stones, cut down their Asherah poles and burn their idols in the fire." (vs 5)
Previously, we have heard God’s intention to make Himself known to the heathen nations through the Israelites. Of course, one way of doing that in the ancient world was to destroy things. Whoever had the "strongest god" would win on the battlefield, so being able to totally destroy another nation was a pretty clear indication that your god was the strongest. That would be a message to the heathen peoples... but would any of them be left to hear it? How can you get a message across to people you’re destroying? Was that God’s intention?
I don’t think it was. As we saw several chapters ago, I think God’s ideal plan was to drive these nations out of the land where the Israelites were going to live. Then, through interaction with Israel, these other nations would gain an understanding of the true God. However, not only did the Israelites seem inclined to fight, but these heathen nations were also warmongers. More often than not, when the Israelites defeated and wiped out an enemy in Canaan, it was the Canaanites who had come to attack — not the other way around.
And anyways, what was so special about the Israelites? Why did God "choose" them over the Canaanites or the Amorites or the Amalekites? It certainly wasn’t because of anything they did. Even in this chapter, Moses reminds them that they weren’t chosen because they were advantageous to God: "The Lord did not set his affection on you and choose you because you were more numerous than other peoples, for you were the fewest of all peoples." (vs 7)
No, I think the scary truth is that God chose the Israelites because — out of all the nations He had to choose from — they were the most willing and able to listen to God. Now you can see why I said this was a scary truth, because the truth was, most of the time, they didn’t even listen to God! Once they got into the Promised Land, they forgot all about God, they didn’t do what He told them to do, and they ended up spending most of their time running after non-existent gods. Still, I think they were chosen by God because they were the "best of the worst."
Above all, I think it’s important for us to remember (though it may be hard to see on the surface) that the promises of God to the Israelites here were about their role as His people on the Earth, not about their eternal life. And the same is true for the heathen nations. Just because a Canaanite king didn’t like the Israelites in his land, went to war with them, and ended up seeing his nation destroyed, doesn’t mean that some of the "heathen" casualties weren’t innocent children or good men and women.
In bringing the Israelites into the Promised Land, God wasn’t trying to achieve their salvation. He was trying to position a group of people who knew Him in the best possible place to witness about Him to others. God didn’t "choose" them for salvation. He "chose" them to do a job. And that job was to communicate that God "chooses" us all for salvation. He is not nationalistic. He loves everyone!