KJV: And the LORD said unto him, Therefore whosoever slayeth Cain, vengeance shall be taken on him sevenfold. And the LORD set a mark upon Cain, lest any finding him should kill him.
NASB: So the LORD said to him, "Therefore whoever kills Cain, vengeance will be taken on him sevenfold." And the LORD appointed a sign for Cain, so that no one finding him would slay him.