Genesis 4:15

4:15 But the Lord said to him, “All right then, if anyone kills Cain, Cain will be avenged seven times as much.” Then the Lord put a special mark on Cain so that no one who found him would strike him down.

Genesis 4:24

4:24 If Cain is to be avenged seven times as much,

then Lamech seventy-seven times!”