I’ve been wrestling with the ethical issues surrounding Joshua’s conquest for the last couple posts. In the last one, I set some groundwork regarding the people (Canaanites) and the land (Canaan). This doesn’t solve all the moral problems, but it does put us in a better place to tackle the question: How could the God of love command a wholesale slaughter of the Canaanites?
In this post, I’d like to talk about one important feature in the Canaanite conquest: God’s preemptive strike of grace.
God commanded Joshua to eliminate the Canaanites, though not without warning. This point is often missed—or ignored—by skeptics who highlight the shear brutality of the conquest. Way back in Genesis 15, God told Abram that he would have to wait 430 years before his people would take full ownership of the land. The reason is that “the iniquity of the Amorites [one of the Canaanite nations] is not yet complete” (Gen. 15:16). In other words, though the Canaanites were sinful (aren’t we all?), they hadn’t exhausted God’s patience yet. They had 430 years to turn from their wickedness to the God of Israel.
But would such a “turn to God” have been realistic? After all, how would they know about this God of Israel?
Good question. One that the Bible clearly answers. After God wrecked havoc on Egypt and brought his people through the Red Sea, His divine power was broadcasted across the world. 
All the nations knew about this God of Israel, even those living in Canaan. The Canaanites living in the city of Gibeon are a case in point. After Israel entered the land, the citizens of Gibeon came to Joshua and said: “we have heard a report of Him, and all that He did in Egypt” (Josh. 9:9). Therefore, “We are your servants. Come now, make a covenant with us” (Josh. 9:11). God trumpeted his reputation across the ancient world, and these particular Canaanites not only heard it but turned to Him (albeit through espionage).
The most well-known example of someone accepting God’s preemptive strike of grace was Rahab, the prostitute living in Jericho. Like the Gibeonites, Rahab says that all the people of Jericho “have heard how the LORD dried up the water of the Red Sea…and as soon as we heard it, our hearts melted, and there was no spirit left in any man because of you” (Josh. 2:10-11). Even though they all came face to face with God’s grace and could have accepted it, only Rahab would go on to confess that “the LORD your God, he is God in the heavens above and on the earth beneath” (Josh. 2:11). Instantly, God removed her sins as far as the east is from the west. But the rest of the people of Jericho and many other Canaanite cities chose to remain in their wickedness and oppose the God of Israel.
But even if they didn’t believe the report they heard about the God of Israel, Joshua intentionally had his soldiers march 
around the city for seven days. Think about it. Jericho probably only contained a few hundred people (a few thousand at best), and Israel numbered around 600,000! The soldiers in Jericho had 7 days to give into what was clearly an inevitable victory for the Israelites. And yet they chose to reject the God of Israel and defend their city. The point being: the 7 day march around the city was yet another offer of grace by the God of Israel, an offer taken up by Rahab yet rejected by the rest of Jericho’s inhabitants. Grace: God’s preemptive strike.
Again, there still remains moral problems with the conquest that we will get to. (What about the slaughter of women and children?) But before we do, we need to have a more thorough perspective on what we are dealing with. In sum, the conquest was the Creator’s punishment for extreme and relentless wickedness among people living in God’s special residence, who rejected clear and undeserved offers of grace. Whatever you think about the conquest as a whole, you have to distinguish between arbitrary killing—genocide—and retributive punishment. Old Testament scholar Christopher Wright articulates it well:
“There is a huge moral difference between arbitrary violence and violence inflicted within the moral framework of punishment” (Wright, Old Testament Ethics, 476).
The conquest, like the flood, was divine capital punishment after hundreds of years of rejected grace.