“The LORD also spake unto Joshua, saying, Speak to the children of Israel, saying, Appoint out for you cities of refuge, whereof I spake unto you by the hand of Moses: That the slayer that killeth any person unawares and unwittingly may flee thither: and they shall be your refuge from the avenger of blood. And when he that doth flee unto one of those cities shall stand at the entering of the gate of the city, and shall declare his cause in the ears of the elders of that city, they shall take him into the city unto them, and give him a place, that he may dwell among them.
And if the avenger of blood pursue after him, then they shall not deliver the slayer up into his hand; because he smote his neighbour unwittingly, and hated him not beforetime.
And he shall dwell in that city, until he stand before the congregation for judgment, and until the death of the high priest that shall be in those days: then shall the slayer return, and come unto his own city, and unto his own house, unto the city from whence he fled.” (Joshua 20:1-6)
In Genesis 9:5-6 God had established the penalty for killing a human being. “And surely your blood of your lives will I require; at the hand of every beast will I require it, and at the hand of man; at the hand of every man's brother will I require the life of man. Whoso sheddeth man's blood, by man shall his blood be shed: for in the image of God made he man.” The Law was equally explicit that they were not to kill people. Unfortunately some wish to expand that prohibition to animals as well, but the law limited it to humans, because unlike the animals, they were created in the image of God, and killing them is by implication an attack on God.
Justice requires that the guilty give up what ever they have taken from the victim. Exodus 21:23-25 instructs, “And if any mischief follow, then thou shalt give life for life, Eye for eye, tooth for tooth, hand for hand, foot for foot, Burning for burning, wound for wound, stripe for stripe." In cases of theft or property damage, the repayment can be restored to the victim, but when he died it cannot. Nevertheless, justice requires that the killer give up what he took from another.
The Law did distinguish between intentional killing, or murder, and death as a result of negligence, or manslaughter. Intentional murder was to be punished by executing the murderer. He gave up his life completely, as justice for having taken the life of another. It also ensured he would not do it again.
In deaths resulting from negligence, the victim still lost his life, but the perpetrator had not deliberately taken it. Justice still required he give up his life. The law required a life sentence. In Numbers 35, God had described the establishment of cities of refuge to provide for such cases. They would provide protection until a trial could be conducted, and if it was determined that the death had been unintentional, the perpetrator could voluntarily remain in the city for the rest of his life , or until the current high priest died. If he left the city, he was to be immediately executed. The death of the current high priest provided a parole. If the killing proved deliberate, the perpetrator was to be killed on the spot. Either way, life was given for life, and Justice was served.
“And they appointed Kedesh in Galilee in mount Naphtali, and Shechem in mount Ephraim, and Kirjatharba, which is Hebron, in the mountain of Judah. And on the other side Jordan by Jericho eastward, they assigned Bezer in the wilderness upon the plain out of the tribe of Reuben, and Ramoth in Gilead out of the tribe of Gad, and Golan in Bashan out of the tribe of Manasseh.” (Judges 20:7-8)
The location of these six cities of refuge ensured that there was one within a day or two’s travel from anywhere in Israel. If one didn’t waste time trying to conceal the crime one could be fairly sure of obtaining protection, but any delay increased the risk of getting caught.
“These were the cities appointed for all the children of Israel, and for the stranger that sojourneth among them, that whosoever killeth any person at unawares might flee thither, and not die by the hand of the avenger of blood, until he stood before the congregation.” (Joshua 20:9)
These cities were selected to ensure that the accused was not unfairly executed without a proper hearing. They were part of the Levites’ inheritance, as was commanded in Numbers 35:6. “And among the cities which ye shall give unto the Levites there shall be six cities for refuge, which ye shall appoint for the manslayer, that he may flee thither: and to them ye shall add forty and two cities.”