Genesis 4:15-16
Genesis 4:15-16 ASV
And Jehovah said unto him, Therefore whosoever slayeth Cain, vengeance shall be taken on him sevenfold. And Jehovah appointed a sign for Cain, lest any finding him should smite him. And Cain went out from the presence of Jehovah, and dwelt in the land of Nod, on the east of Eden.