Numbers 33:44-19
Why did God permit avenging blood and yet forbid murder?
PROBLEM: God forbade murder (Exodus 20:13). Yet here He says, “The avenger of blood himself shall put the murderer to death; when he meets him, he shall put him to death.”
SOLUTION: First of all, this was not an act of murder, but an act of capital punishment which God had ordained before the law (Genesis 9:6), and Moses had reaffirmed it under the Law (Exodus 21:12). Further, notice that it was only to be done to a “murderer,” not simply to anyone. Also, the avenger had to be the nearest male relative of the one who was murdered, not just anyone who wished to take justice in his own hands. In short, what is forbidden in Exodus 20 is the recognized crime of murder, and what is permitted in Numbers 35 is the recognized responsibility of capital punishment. These are not in conflict.