Old John Gill has an interesting comment of this ending to the Book of Job..
He had also seven sons, and three daughters. The same number of children, and of the same sort he had before, Job 1:2; and according to Nachman the very same he had before, which the additional letter in the word “seven” is with him the notification of; so that the doubting of what he had before, Job 42:10; respects only his substance, and particularly his cattle; though the Targum says he had fourteen sons, and so Jarchi (t); others think these may be said to be double to Job in their good qualities, external and internal, in their dispositions, virtues, and graces; and others, inasmuch as his former children were not lost, but lived with God, and would live for ever, they might now be said to be double; and so they consider this as a proof of the immortality of the soul, and of the resurrection of the body; but these senses are not to be trusted to; whether these children were by a former wife or another is uncertain.
(t) Vid. Balmes. Gram. Strat. 26.
And the daughters were special enough to be mentioned by name, though the sons were not.