Deuteronomy 20:12-14

12But they may refuse to agree. They may start to fight against you. If they do that, you must put your soldiers all around the city.

13The Lord your God will give the city to you. Then you must kill all the men there.

14But you can take for yourselves the women, the children, the animals and other valuable things in the city. You can take all these things from your enemies that God gives to you.