Deuteronomy 19:6–12

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.

¹¹But if any man hate his neighbor, and lie in wait for him, and rise up against him, and smite him mortally so that he dieth, and he flee into one of these cities; ¹²then the elders of his city shall send and fetch him thence, and deliver him into the hand of the avenger of blood, that he may die.