According to the biblical narrative in the Book of Genesis, Cain received the Mark of Cain as a form of divine protection and warning. After Cain committed the act of murdering his brother Abel out of jealousy, God confronted him and pronounced a punishment upon him. In Genesis 4:15 (New International Version), it is stated:
"But the Lord said to him, 'Not so; 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."