Numbers 35:11

“Then ye shall appoint your cities to be cities of refuge for you, etc.] And, according to the Jewish writers f510, these were neither to be made large nor little, but middling; and they appointed them where there were markets and fairs, at which goods were to be sold; and where there was plenty of water, and a multitude of people; and where there were but few, they fetched others from other places; and they neither made nets for hunting, nor twisted ropes in them, nor sold any warlike instruments, lest the avenger of blood should use himself to come thither, under pretence of buying such things, and kill the manslayer: that the slayer may flee thither, which killeth any person at unawares;…”

“THE BLOOD AVENGER. (Num. 35:9-34) that the slayer may flee thither, which killeth any person at unawares--The practice of Goelism, that is, of the nearest relation of an individual who was killed being bound to demand satisfaction from the author of his death, existed from a very remote antiquity (Gen 4:14; Gen 27:45). It seems to have been an established usage in the age of Moses; and although in a rude and imperfect state of society, it is a natural and intelligible principle of criminal jurisprudence, it is liable to many great abuses; the chief of the evils inseparable from it is that the kinsman, who is bound in duty and honor to execute justice, will often be precipitate--little…”

“Unawares - Not wilfully, designedly or maliciously, but through mistake or indiscretion. Numbers 35:12”

“ye shall appoint: As the goel, or kinsman, had a right to avenge the death of his relation, by slaying the murderer wherever he found him, the appointment of these cities was a humane institution for the protection of the involuntary homicide; for they were designed only for the protection of such Num 35:6; Jos 20:2 unawares: Heb. by error, Num 35:22, Num 35:23; Exo 21:13; Deu 4:42, Deu 19:4, Deu 19:5 Numbers 35:12”