Deuteronomy 19:2-4

American Standard Version

² thou shalt set apart three cities for thee in the midst of thy land, which Jehovah thy God giveth thee to possess it. ³ Thou shalt prepare thee the way, and divide the borders of thy land, which Jehovah thy God causeth thee to inherit, into three parts, that every manslayer may flee thither.

⁴ And this is the case of the manslayer, that shall flee thither and live: whoso killeth his neighbor unawares, and hated him not in time past;