10-11 When you march up to attack a city, make its people an offer of peace. If they accept and open their gates, all the people in it shall be subject to forced labour and shall work for you. 12-13 If they refuse to make peace and they engage you in battle, lay siege to that city. When the Lord your God delivers it into your hand, put to the sword all the men in it. 14 As for the women, the children, the livestock and everything else in the city, you may take these as plunder for yourselves. And you may use the plunder the Lord your God gives you from your enemies. 15 This is how you are to treat all the cities that are at a distance from you and do not belong to the nations nearby.

16-17 However, in the cities of the nations the Lord your God is giving you as an inheritance, do not leave alive anything that breathes. Completely destroy them - the Hittites, Amorites, Canaanites, Perizzites, Hivites and Jebusites - as the Lord your God has commanded you. 18 Otherwise, they will teach you to follow all the detestable things they do in worshiping their gods, and you will sin against the Lord your God.

19-20 When you lay siege to a city for a long time, fighting against it to capture it, do not destroy its trees by putting an axe to them, because you can eat their fruit. Do not cut them down. Are the trees people, that you should besiege them? However, you may cut down trees that you know are not fruit trees and use them to build siege works until the city at war with you falls. Deuteronomy 20:10-20 New International Version (English Standard Version link)

Is the Bible cruel? After reading today's verses many would say yes. But we must remember that we live in a time when the world has had 2000 years of the gospel Jesus brought. God gave those commands to Moses over 4000 years ago when much heathen darkness filled the earth. So, in the case of nations far from Israel, terms of peace were offered. But, in the case of nations in the land where they were going to live, it was to be total destruction. Why was that? (vs 18)

God did not want Israel to adopt the terrible things those nations did. Moses described some of those things in Chapter 18 when he said: “When you enter the land the Lord your God is giving you, be very careful not to imitate the detestable customs of the nations living there. For example, never sacrifice your son or daughter as a burnt offering. And don't let your people practice fortune-telling, or use sorcery, or interpret omens, or engage in witchcraft, or cast spells.”

The Book of Leviticus tells us also of the great sexual immorality that dominated those cultures, and it makes heavy and tragic reading. This is what God said to Israel. “Do not act like the people in Egypt, where you used to live, or like the people of Canaan, where I am taking you. You must not imitate their way of life! You must never have sexual relations with a close relative, for I am the Lord. Do not violate your father by having sexual relations with your mother. Do not have sexual relations with your sister or half sister, whether she is your father’s daughter or your mother’s daughter. Do not have sexual relations with your granddaughter, whether she is your son’s daughter or your daughter’s daughter,  Do not defile yourself by having sexual intercourse with your neighbour’s wife. Do not practice homosexuality, having sex with another man as with a woman. It is a detestable sin. A man must not defile himself by having sex with an animal. And a woman must not offer herself to a male animal to have intercourse with it. This is a perverse act.” (Leviticus 18:6-23)

The reason for destroying those nations as an act of God's judgement is seen in Leviticus 18:24-27 where God says: “Do not defile yourselves in any of these ways, for the people I am driving out before you have defiled themselves in all these ways. Because the entire land has become defiled, I am punishing the people who live there. I will cause the land to vomit them out. All these detestable activities are practiced by the people of the land where I am taking you, and this is how the land has become defiled.”

The Bible isn't cruel – it is honest. Depravity will result in judgment and destruction. But God also sent a Saviour for all who will repent, even of the terrible deeds described in Leviticus.