Thus all the days of Seth were 912 years, and he died.
We have here all that the Holy Ghost thought fit to leave upon record concerning five of the patriarchs before the flood, Seth, Enos, Cainan, Mahalaleel, and Jared. There is nothing observable concerning any of these particularly, though we have reason to think they were men of eminence, both for prudence and piety, in their day: but in general, I. Observe how largely and expressly their generations are recorded.
Commenting on Genesis 5:6-20
And Enos lived ninety years, and begat Cainan. According to the Septuagint a hundred and ninety years; it can hardly be thought but that he had sons or daughters before, but this is only taken notice of for a reason before given. And Enos lived ninety years, and begat Cainan.
And all the days of Seth were nine hundred and twelve years: and he died. (e) The main reason for long life in the first age, was the multiplication of mankind, that according to God's commandment at the beginning the world might be filled with people, who would universally praise him.