The Ancient Hebrew tribes considered it to be the duty of the individual and family to avenge evil in God's name. The person who put the initial aggressive killer to death was given a special name: "go'el haddam", the blood-avenger or blood-redeemer (Num. 35: 19, etc.). Six cities of refuge were made to provide a "cooling off" phase as well as due process for the accused. As the "Oxford Companion to the Bible" states: "Since life was viewed as sacred (Gen. 9.6), no amount of blood money could be given as recompense for the loss of the life of an innocent person; it had to be 'life for life'" (Exod. 21.23; Deut. 19.21)".