And surely your blood of your lives will I require; at the hand of every beast will I require it, and at the hand of man; at the hand of every man's brother will I require the life of man. Genesis 9:5
From the beginning, vengeance for blood is a biblical command from God.
Vengeance is Mine, and recompense; Their foot shall slip in due time; Deuteronomy 32:35
Their due time is coming soon. Either from the hand of man or from the hand of God.