Genesis 5:8

And all the days of Seth were nine hundred and twelve years: and he died.

And all the days of Seth were nine hundred and twelve years, and he died. As his father Adam before him. Seth, according to Josephus {l}, was a very good man, and brought up his children well, who trod in his steps, and who studied the nature of the heavenly bodies; and that the knowledge of these things they had acquired might not be lost, remembering a prophecy of Adam, that the world should be destroyed both by fire and by water, they erected two pillars, called Seth's pillars; the one was made of brick, and the other of stone, on which they inscribed their observations, that so if that of brick was destroyed by a flood, that of stone might remain; and which the above writer says continued in his time in the land of Siriad. The Arabic writers {m} make Seth to be the inventor of the Hebrew letters, and say, that when he was about to die he called to him Enos, Cainan, Mahalaleel, Jared, Enoch, their wives and children, and adjured them by the blood of Abel not to descend from the mountain where they dwelt, after the death of Adam, nor suffer any of their children to go to, or mix with any of the seed of Cain, which were in the valley; whom he blessed, and ordered by his will to serve the Lord, and then died in the year of his age nine hundred and twelve, on the third day of the week of the month Ab (which answers to part of July and part of August), A. M. 1142, and his sons buried him in the hidden cave in the holy mountain, and mourned for him forty days.

{l} Antiqu. l. 1. c. 2. sect. 3.
{m} Elmacinus, Patricides, apud Hottinger, p. 228, 229.