New Defender's Study Bible Notes
4:24 sevenfold. A Jewish tradition (no more than that) suggests that one of the men slain by Lamech was his ancestor, Cain himself. In any case, Lamech’s boast is nothing less than blasphemy against God in promising protection for Cain.
4:24 seventy and sevenfold. Contrast Lamech’s vindictiveness with the forgiving attitude enjoyed by Christ, who urged Peter to forgive his brother seventy times seven times (Matthew 18:22).