Numbers 35:21

Or in enmity smite him with his hand, that he die: he that smote him shall surely be put to death; for he is a murderer: the revenger of blood shall slay the murderer, when he meeteth him.

Cross-reference

In Numbers 35:19, the identical command is given—the avenger of blood must execute the murderer, repeating this verse’s instruction.

In Exodus 21:14, the same law appears: deliberate murderers are to be put to death, matching the penalty prescribed here.

In Genesis 4:14, Cain fears being killed by anyone, reflecting the blood‑avenger principle stated here—murderers face execution.