There are at least five things to remember as we seek to process the violence that opens the book of Judges.
The first thing is that these commands were specific to these specific people. It would be another thing altogether if the Lord were inciting us all to this kind of war; but he’s not; he spoke to these particular people at this particular time. That’s important.
The second thing I want you to remember is the cruelty and the evil of these Canaanite lands. These are people who were torturers; slave-drivers; and people who routinely put their children in the fire in order to appease their demonic-gods.
I think most of us would agree that if any nation in the world today was publicly and consistently burning children alive, we would expect—and even petition for—our government to intervene, with military-force if necessary. So, what we have here at the beginning of Judges is a written record of that kind of action taking place. It was unheard of for any nation to take a stand in the way that the ancient-church did in that day, but they bravely did, and for that they should be commended.
The third thing I would remind you of is the patience of the Lord with these nations. As far back as Genesis 15, the LORD told Abraham that his descendants would have to remain slaves in Egypt for 400 years before taking possession of Canaan, ‘the iniquity of the Amorites is not yet complete’ he says. The Lord has shown such patience with these Canaanite nations!
Fourthly, remember that there was hope for anyone in these nations who looked to the Lord Jesus in repentance and joined the church. Rahab is a good example of someone like that who found mercy; all of them could have done so, but they chose to reject Christ and were punished for doing so.
But fifthly and finally, the point of these sections is for us to be given pre-warning about the day of judgement. So what we have here is not a general guide to how for how to fight wars, no, it’s a specific authorization from the Lord to utterly destroy these specific Canaanite nations, which gives us a vivid picture of how it will be on that final day. The Book of Revelation discusses the judgement of the Lord in much the same way as the judgement against the Canaanite nations took place. It’s terrifying and its comprehensive. We must look to the Lord Jesus before the day of wrath comes.