'Avenger of Blood' in the Bible

The avenger of blood shall himself put the murderer to death: when he meets him, he shall put him to death.

or in enmity struck him with his hand, so that he died; he who struck him shall surely be put to death; he is a murderer: the avenger of blood shall put the murderer to death, when he meets him.

then the congregation shall judge between the striker and the avenger of blood according to these ordinances;

and the congregation shall deliver the manslayer out of the hand of the avenger of blood, and the congregation shall restore him to his city of refuge, where he was fled: and he shall dwell therein until the death of the high priest, who was anointed with the holy oil.

and the avenger of blood find him outside of the border of his city of refuge, and the avenger of blood kill the manslayer; he shall not be guilty of blood,