Numbers 35:11

Ye shall appoint - cities of refuge - The cities of refuge among the Israelites were widely different from the asyla among the Greeks and Romans, as also from the privileged altars among the Roman Catholics. Those among the Hebrews were for the protection of such only as had slain a person involuntarily. The temples and altars among the latter often served for the protection of the most profligate characters. Cities of refuge among the Hebrews were necessary, because the old patriarchal law still remained in force, viz., that the nearest akin had a right to avenge the death of his relation by slaying the murderer; for the original law enacted that whosoever shed man's blood, by man should his blood be shed, Genesis 9:6, and none was judged so proper to execute this law as the man who was nearest akin to the deceased. As many rash executions of this law might take place, from the very nature of the thing, it was deemed necessary to qualify its claims, and prevent injustice; and the cities of refuge were judged proper for this purpose. Nor do we ever read that they were ever found inefficient, or that they were ever abused.

35:11 Unawares - Not wilfully, designedly or maliciously, but through mistake or indiscretion.