After the Flood God gave Noah the law that "he who sheds man's blood, by man his blood will be shed" (Gen. 9:6).
The law established the distinction between murderer and murderer; When a person was accidentally killed, the murderer could flee to one of the cities of refuge (see CITIES OF REFUGE) to be protected there from the avenger of blood.
Then it was considered that the executor of justice should be the closest relative of the murdered person.
God has invested man with governmental authority to maintain in force this universal command, given long before the Law of Moses, and which has never been revoked or mitigated.
In the NT it is mentioned that the magistrate does not carry the sword in vain, because he is a servant of God to punish those who do evil (Rom. 13).
Under the Law of Moses, “an eye for an eye and a tooth for a tooth” was enacted (Mt. 5:38; Ex. 21:24). For the Christian it is totally different: having been treated in grace, he must also act towards others with this same spirit of grace.
What he is told is: “Do not avenge yourselves, my beloved, but leave room for the wrath of God; for it is written, 'Vengeance is mine, I will repay, says the Lord' (Rom. 12:19; Rev. 6:10; 19:2).
Now is the day of grace; But the day of vengeance is approaching that will fall on those “who do not know God, nor obey the gospel of our Lord Jesus Christ” (2 Thes. 1:8).
The Christian's duty not to take revenge does not conflict in any way with the exercise of God's government by the magistrates, who derive their authority from Him in the repression and retribution of evil.
Meaning of BLOOD AVENGER
After the Flood God gave Noah the law that "he who sheds man's blood, by man his blood will be shed" (Gen. 9:6).