Genesis 4:24

4:23 Then Lamech said to his wives: "Adah and Zillah, hear my voice; Wives of Lamech, listen to my speech! For I have killed a man for wounding me, Even a young man for hurting me.

4:24 If Cain shall be avenged sevenfold, Then Lamech seventy-sevenfold."

4:25 And Adam knew his wife again, and she bore a son and named him Seth, "For God has appointed another seed for me instead of Abel, whom Cain killed."