The answer
The scriptures does not tell us exactly whom Lamech killed. We are told that Lameh had killed a young man in self-defense. He didn't try to hide anything. On the contrary, he bragged about being a killer; and was proud to be the kind of man who would kill anybody that dared to touch him. Lamech thought if God had promised to avenge Cain (protect him) sevenfold, who did not act in self-defense; then in fairness, He must avenge him seventy and seven fold.Answered by His Eminence Metropolitan Youssef (opens in a new tab)