Deuteronomy 20:8-11

Then the officers shall speak further to the people and say, ‘Who is the man that is afraid and fainthearted? Let him depart and return to his house, so that he might not make his brothers’ hearts melt like his heart.’ When the officers have finished speaking to the people, they shall appoint commanders of armies at the head of the people. “When you approach a city to fight against it, you shall offer it terms of peace. If it agrees to make peace with you and opens to you, then all the people who are found in it shall become your forced labor and shall serve you.