Deuteronomy 20:10 in the King James Version
When thou comest nigh unto a city to fight against it, then proclaim peace unto it.
Context
9 It shall be, when the officers have finished speaking to the people, that they shall appoint captains of armies at the head of the people.
10 When you draw near to a city to fight against it, then proclaim peace to it.
11 It shall be, if it gives you answer of peace and opens to you, then it shall be that all the people who are found therein shall become forced laborers to you, and shall serve you.