Blood in Fausset's Bible Dictionary

THE AVENGING OF BLOOD by the nearest kinsman of the deceased was a usage from the earliest historical times (Genesis 9:5-6; Genesis 34:30; 2 Samuel 14:7). Among the Bedouin Arabs the thar, or law of blood, comes into effect if the offer of money satisfaction be refused. So among the Anglo-Saxons the wer-gild, or money satisfaction for homicide, varying in amount according to the rank, was customary. The Mosaic law mitigated the severity of the law of private revenge for blood, by providing six cities of refuge (among the 48 Levitical cities), three on one side of Jordan, three on the other, for the involuntary homicide to flee into. The avenger, or goel (derived from a Hebrew root "pollution," implying that he was deemed polluted until the blood of his slain kinsman was expiated), was nearest of kin to the man slain, and was bound to take vengeance on the manslayer. If the latter reached one of the six cities, (Kedesh in Naphtali, Shechem in mount Ephraim, Hebron in the hill country of Judah, W. of Jordan; Bezor in Reuben, Ramoth in Gilead (Gad), Golan in Manasseh, E. of Jordan,) he was safe until the elders of the city, and then those of his own city, decided whether it was an involuntary act. In this case he was kept safe from the avenger in the city of refuge, so long as he did not go 2,000 cubits beyond its precincts. After the high priest's death he might return home in safety (Numbers 35:25; Numbers 35:28; Joshua 20:4-6). The roads were to be kept clear, that nothing might retard the flight of the manslayer, to whom every moment was precious (Deuteronomy 19:3). Jewish tradition adds that posts inscribed "Refuge," "Refuge," were to be set up at the cross roads. All necessaries of water, etc., were in the cities.