Deuteronomy 19:2-10

2thou shalt set apart three cities for thee in the midst of thy land, which Jehovah thy God giveth thee to possess it. 3Thou 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.

4And 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; 5as when a man goeth into the forest with his neighbor to hew wood, and his hand fetcheth a stroke with the axe to cut down the tree, and the head slippeth from the helve, and lighteth upon his neighbor, so that he dieth; he shall flee unto one of these cities and live: 6lest the avenger of blood pursue the manslayer, while his heart is hot, and overtake him, because the way is long, and smite him mortally; whereas he was not worthy of death, inasmuch as he hated him not in time past. 7Wherefore I command thee, saying, Thou shalt set apart three cities for thee. 8And if Jehovah thy God enlarge thy border, as he hath sworn unto thy fathers, and give thee all the land which he promised to give unto thy fathers; 9if thou shalt keep all this commandment to do it, which I command thee this day, to love Jehovah thy God, and to walk ever in his ways; then shalt thou add three cities more for thee, besides these three: 10that innocent blood be not shed in the midst of thy land, which Jehovah thy God giveth thee for an inheritance, and so blood be upon thee.