Today you should read: Deuteronomy 20:1-20
Remember that the book of Deuteronomy can be broken down into an application of the Ten Commandments. Today’s passage is unpacking and applying more of the commandment not to murder. Here’s how it breaks down:
Verses 1-4: Even though the army of Israel was fighting armies much bigger than itself, God wants them to have confidence, not because of their own merit, but because of God’s hand in providing victory. This is a great example for us to keep in mind context when interpreting passages like this. Just because God says he will provide victory for the Israelites taking the promised land doesn’t mean you can use these verses as proof that God will give victory for every battle you face in life. What we can apply is that God is a God who keeps his promises even when the practicalities seem insurmountable.
Verses 5-8: These give excuses for abstaining from military service. “The priority is on enjoying the blessings from God in housing, crops, and marriage.” (ESV Study Bible) It also excuses those who are anxious or worried about fighting. On first glance, this seems almost silly or irrational—isn’t everyone afraid of war? But for those that are not able to overcome their initial fear and remember the promises of God, it is better that they be absent than their fear and lack of trust spread throughout the camp.
Verses 10-20: These verses talk about how the people of Israel should take the land. The main thing to see is that the land that is being taken should be given the opportunity to surrender peacefully.
By: Graham Withers — Pastoral Ministry Apprentice
JumpstartCPC.com 
I have two questions:
1. When he’s giving them an out from battling, how can they go home to dedicate a house? They were nomadic.
2. In regard as to whether to kill all or allow their enemies to live, why were some cities (the one’s of their inheritance and then the others) different in how they could potentially contaminate the Israelites? Weren’t they all pagans?
To your first question Lindsay, I honestly wasn’t able to find a whole lot of information regarding that. My guess is that even though they were nomadic, they would often settle in some places for extended periods of time, and they might have a different type of structure to dwell in.
For your second question, it comes down to what cities were in the Promised Land. Cities that were not where they would eventually dwell were not as much of a threat to negatively influence the people away from God or were a threat for retaliation, and were therefore not treated as harshly as those that would be within the land they would take.
I couldn’t find anything on my first question either, and I LOOKED!
Thanks for your response Graham!