It is true that God compensated Job by repaying him twice as much as He had taken, but what about all those other men, in whose name no book was ever written, men deprived of everything and given nothing in return, to whom everything was promised and nothing fulfilled.
(Trans. Giovanni Pontiero)
In his sorrow and his attempt to overcome his error, Joseph tries to have as many children as possible with Mary and they do have many, but he cannot replace all of the children. In such a context, the narrator of the tale brings in a story of a man who lost all of his children and receives "replacements" at the end of the tale--twice as many sons and daughters. But can they ever really be "replaced"? How can you possibly replace a life, particularly your own child's? Even if Joseph could numerically account for all the children killed by Herod's men, that is not a replacement. But this passage indicates that Job, a special case in righteousness, a special case in suffering, is also a special case in repayment: no one else seems to get repaid double or even equivalent of what was once lost. Promised everything by God, by prophets, by religious and civil authorities, the anonymous ones (those "whose name no book was ever written") receive nothing.