After this lived Job an hundred and forty years. It has been concluded from this statement, combined with that at the close of verse 10, that Job was exactly seventy years of age when his calamities fell upon him; but this is really only a conjecture, since the statement that "God added to all that had been Job's to the double," does not naturally apply to anything but his property.
We may, however, fairly allow that (as Professor Lee says) he "could scarcely have been less than seventy" when his afflictions came, having then a family of ten children, who were all grown up (Job 1:4).
In this case, the whole duration of his life would have been 210 years, or a little more, which cannot be regarded as incredible by those who accept the ages of the patriarchs, from Peleg to Jacob, as respectively 239, 230, 148, 205, 175, 180, and 147 years.
And saw his sons, and his sons' sons; i.e. his descendants—grandchildren, and great-grandchildren. Even four generations. According to the Hebrew inclusive practice of reckoning, we may regard his own generation as included.