Deuteronomy 20:8-11

And the officers shall speak further to the people, and say, ‘Is there any man who is fearful and fainthearted? Let him go back to his house, lest he make the heart of his fellows melt like his own.’ And when the officers have finished speaking to the people, then commanders shall be appointed at the head of the people. “When you draw near to a city to fight against it, offer terms of peace to it. And if it responds to you peaceably and it opens to you, then all the people who are found in it shall do forced labor for you and shall serve you.