Joshua 11

This chapter introduces an interesting military issue that will recur: the use of chariots in fighting in the level places, a skill which the Israelites lacked and suffered sorely from that lack. But, thanks to God's assistance, Joshua surprises the cavalry while it is resting by the Waters of Merom and routs them. The Israelites capture the horses, but rather than using them or eating them, they hamstring them.

The battles of this chapter occur in the far north of Israel, in areas near the Syrian and Lebanese borders and including the important port city of Tyre. This part of Israel will be occupied by the clans of Asher and Naphthali.

Finally, Joshua completes the conquest of the south, not however managing to take the coastal cities of Gaza and Ashdod, or Gath, cities that will later prove to be thorns in the side of the Israelites. Jerusalem remains unconquered. Indeed, it will gradually develop that rather than subduing Canaan, the Israelites have grasped a tiger by the tail and will be harried from all sides, with occasional victories under the judges, until they unify under David (http://www.cresourcei.org/conquest.html)

In this chapter, we are told that God Himself hardened the hearts of the Canaanites, inciting them to attack Israel. This is as close an answer as we will get to the genocide.