Repetition of "and he begat sons and daughters:" While reading Genesis 5, we can read the development of human race from Adam to Noah, bridging the gap between the two.

During that passage, there's an expression mentioned often


  (...) and he begat sons and daughters:


What's the purpose of such repetition?
That repetition is called epistrophe which is an optional repetition to make a point.

This comes in a context where humans were expelled from paradise (where they were given a clear command we can read in Genesis 1:28, "fruitful and multiply. Fill the earth and govern it. Reign over the fish in the sea, the birds in the sky..."), fear and shame entered the world and there's a sign of redemption.

Even though we can't be sure or know what's in human hearts, i believe by reinforcing the idea humans are now following what God commanded while they were in paradise and not questioning Him, they are either trying to please Him to compensate for their wrongdoings or simply because they trust that's the best.

Quoting Thomas Brooks (1824). “The select works of ... Thomas Brooks".


  Till men have faith in Christ, their best services are but glorious sins.