Genesis 4:14-15

14Today you are driving me from the land, and I will be hidden from your presence; I will be a restless wanderer on the earth, and whoever finds me will kill me.” 15But the LORD said to him, “Not so Septuagint, Vulgate and Syriac; Hebrew Very well ; anyone who kills Cain will suffer vengeance seven times over.” Then the LORD put a mark on Cain so that no one who found him would kill him.