In class we heard a few good quotes as possible explanations for violence in the Bible.
If I understand right, this is what a Hebrew Rabbi, Abraham Heschel says: Divine wrath is good news for the oppressed. If you worship a God of peace, maybe you worship the status quo. (check out his Wikipedia)
My profs proffered that in fact Pax Romana (Roman Peace) was a way to keep revolt from happening in their conquered nations. I think what they were trying to say was that the dictate for peace kept wicked people wicked, and oppressed people oppressed.
Also, the surrounding cultures in the times of the Old Testament were all about war. And God seems to come to nations in the way they will understand, in customs they’re vaguely familiar with. It’s like God said, this isn’t my natural way, but just to prove that I am most powerful in war, which is so prevalent in your lives, I will show that I can conquer in that way as well. But God only gives permission to do it once, then he disbands the armies. So Israelites were the abnormally peaceful ones.
And anyway most of the actual violence happens when the nations get confused and kill each other, or a trumpet blast just obliterates a city God said was wicked.
Plus, some archaeologists say that many of these cities were already mostly abandoned by the time the Israelites came through anyway. Which means probably very little killing had to happen in order for everyone to be wiped out.
Just some thoughts that I found interesting.