Shet was born when Adam HaRishon was 130 years old and lived 912 years [(and in Yuchasin it is written 872, a mistake)] and died 42 years into the second millennium [(and in Yuchasin it is written 62, he went according to his error)]. The nations say that when Adam gave birth to Shet, it was then a time of great light [(Sha'arei Kedusha 21)]. After Shet gave birth to Adam, according to the gentiles, he had sixty children and daughters [(Yuchasin at the beginning of the article)].

And it is said in Bereshit Rabbah that when HaShem saw the world empty of human beings and uninhabited, He observed many generations of men and they all gave birth to twins [(Sha'arei Kedusha 7)].

Shet commanded his sons not to associate with the descendants of Cain, and thus they acted until the seventh generation. Then they associated, and from them were born the giants, who greatly increased in sin until they perished in the Flood [(Sh"K 92)].

What [][the Torah mentions only one man in each generation, some say that the generations delayed in giving birth due to the weakness of their nature until the number of years that the Torah testifies to, and the Rambam in the Guide for the Perplexed wrote that long life was granted only to the man mentioned in the Torah, but the rest of the generation lived natural years. The Ramban wrote that the power of their offspring was delayed until the time mentioned in the Torah.

Some say that the scripture did not consider it necessary to mention except for the worthy son who would come from him. Some say that from our years to the present, there were ten years for the earlier generations (see above, 1897, which contradicts this opinion). Some say that their years were lunar years. Some say that because they were eating vegetation and drinking water and were not given to lust, therefore they lived long lives.

However, after the Flood, when it was permitted to eat meat and drink wine, their days were shortened. Some say that their long lives were a matter of miracle. Some say that the years were not truly long, but that the head of that generation commanded his generation laws and customs as he wished, and that the practice of the Torah and that custom continued throughout the time mentioned in the Torah, and it was considered as though he had lived all those years.

Some say that one who wishes to become wise and learn all the natural sciences requires a long time, and in order for His Divinity to be made known, He prolonged their days so that there would be ample time, and what they understood and learned they wrote in a book for the benefit of their generations (see Kabbalah 6)].