Two Lines

Parshat בראשית speaks about two lines of descendants from אדם הראשון. This is often not noticed when reviewing the Parsha. There is the Cain line that lasted only seven generations and ended. This is the reason the wives of Lemech did not want to have children, because they knew that line would become extinct. The second line was the Seth line that carried on the generations to eternity. The only one who survived the Cain line, was Naama, the wife of Noach. This also explains how the father of Noach was Lemech. This was not the same blind Lemech who killed Cain as well as his son. There were two Lemechs, one from the Cain line and the other from the Seth line. One needs to study the Parsha carefully to pick up on this historical fact. There were twenty generations from Adam to Avraham as pointed out in the Torah from the Adam-Seth line.