Avenger of blood
The avenger of blood was a legal role in ancient Israelite society, usually the nearest male relative to a murder victim, who was responsible for seeking justice by killing the murderer. This role was based on the principle of retributive justice and was intended to protect family honor and deter murder, with legal protections (such as cities of refuge) in place to distinguish between willful murder and accidental killing.[1]
God's command for justice predates the Mosaic law, and is found at Gen. 9:6 immediately after all the children of Cain perished in the Great Flood: "Whoever sheds man's blood, by man shall his blood be shed: for in the image of God made he man." In the Christian dispensational tradition, this command by God marks the beginning of the "Dispensation of Human Government".
All three Abrahamic religions, Judaism, Christianity, and Islam recognize the profound severity of taking a life and the societal need for justice.