Genesis 6:1

And it came to pass. This expression does not imply that the conditions here described arose subsequent to events recorded in previous chapters. The author is simply pointing to the state of society in the days of Noah, when ten generations of increasing corruption reached a climax.

Men began to multiply. The human race increased rapidly not only in wickedness but in numbers as well. Among the manifold dangers for pious Sethites were the beautiful daughters of unbelievers. Wives were taken not because of their virtue but for beauty’s sake, with the result that godlessness and wickedness made heavy inroads among Seth’s descendants.