Genesis Chapter 4, Verse 15

15: 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.- edit KJV text
15: And the Lord said to him: No, it shall not so be: but whosoever shall kill Cain, shall be punished sevenfold. And the Lord set a mark upon Cain, that whosoever found him should not kill him.— edit Douay text
15: And the Lord God said to him, Not so, any one that slays Cain shall suffer seven-fold vengeance; and the Lord God set a mark upon Cain that no one that found him might slay him.— edit LXX text