The Book of Job is quite possibly the strangest book in the Hebrew Bible, and is notoriously difficult to date.
In essence, Job is an essay on the problem of evil. The book starts with God and Satan discussing Job, a “perfect and upright” man who “feared God and eschewed evil” (1:1). Satan tells God that Job is only virtuous because he is well off; were he to suffer, he would surely “curse thee to thy face” (1:11). God accepts the challenge and gives Satan permission to destroy Job’s life.
Satan kills his children, destroys his house, bankrupts him and gives him a terrible skin disease. Job’s unnamed wife says to him, “Dost thou still retain thine integrity? curse God, and die” (2:9), but Job stands firm.
The story then stops being a narrative and takes a philosophical bent, with Job’s friends Eliphaz, Bildad and Zophar, each in turn, saying that all reward and punishment comes from God. God is just. Job was punished. Therefore Job must have sinned grievously.
A fourth character then enters the story – Elihu, who accuses Job as well (chapters 32-37). Biblical scholars suspect him to be a later addition to the book, mostly because while the first three friends are mentioned in the introduction, Elihu appears from nowhere.
Either way, Job denies sinning, and calls on the heavens to testify on his behalf. At this point (38:1) God appears from the whirlwind and answers Job’s explicit implication that he is unjust.
Again, many scholars believe this part wasn’t in the original book but was added by a later editor, this time because it seems oddly out of place. God’s explanation - if you can call it that - is that Job, being a mere human, cannot hope to understand his actions. He asks Job a rhetorical question - Did Job kill the Behemoth and the Dragon, as he has? and embarks on an extremely long, poetic ramble describing these two mythological creatures that lasts until the end of chapter 41.
The book then wraps up with a happy ending - Job’s fortunes are restored and he is given a new set of children.
Since the story lacks any historical context and no historic individuals are mentioned, it is very hard to date.
The Talmud (redacted at about 500 CE) has several versions. The Talmud (Bava Barta 14b) says it was written by Moses, but then on the next page (15a), rabbis Jonathan and Eliezer say Job was among those who returned from the Babylonian Exile in 538 BCE, which was about seven centuries after Moses’ supposed death.
The very same page of Talmud suggests that Job is not a real person and that the whole book is just an allegory; also, that Job was the contemporary of Jacob or Abraham.
Modern biblical scholars on the other hand think they do have a clue. There are no historic reference points but they can analyze the language and theology, and compare them with other Hebraic writings of known provenance.
There's a snag, though. The language in Job is unlike any other found in the Bible, or outside it. True, the book is written in Hebrew, but it is very strange Hebrew indeed. It has more unique words than any other book of the Hebrew Bible. The language is archaic, which would indicate that it was very ancient: but it is also heavily influenced by Aramaic, which would make it relatively late.
Theories for the peculiar language range from it being written by Arabian Jews, to it being a poor translation from Aramaic, to the text being written in Idumean, the language of Biblical Edom, of which we have no record - but would have likely been very similar to Hebrew (note that Job is described not as Judean but Idumean).
The most popular theory now is that Job was written by someone whose first language was Aramaic but whose literary language was Hebrew, and that the use of archaic language was deliberate. This would indicate that we are talking about an author or more likely authors living in the early Second Temple period.
Satan at the right hand of God
More telling are the religious beliefs presented in the book, which features Satan as a member of God’s council. But Satan is not mentioned in pre-exilic biblical books. That, taken alone, would indicate that the book was written after the Babylonian Exile.
On the other hand, Satan is not presented as an all-powerful force of evil, as he is in Chronicles. As Chronicles is believed to have been written in the 4th century BCE, Job would have been written before that. If anything, Job's Satan is most similar to the Satan of the Book of Zechariah, written in the early Second Temple period, which may indicate that Job was written during the same period - the late 6th century BCE or the early 5th BCE.
Similarly, the Book of Job does not mention reward and punishment in the afterlife. If the author had been aware of these beliefs, surely the possibility of Job receiving his just reward after death would have been presented.
This again supports dating the book to the early Second Temple period, as the belief in reward and punishment in the afterlife appears clearly for the first time in the Book of Daniel, in a section believed to have been written in the second century BCE.
There is no question that the book was already written by the second century BCE, since an Aramaic translation of the Book of Job was discovered among the Dead Sea Scrolls.
Archaeological signs from deep antiquity
Even if the story of Job was written down during the early Second Temple era (late 6th century BCE to the early 4th century BCE), that doesn’t mean the story was a new one. In fact, we know that it was extremely ancient.
Ezekiel (about 622 to 570 BCE) mentions Job together with Noah and Daniel as men of ancient renown (Ezekiel 14:14). This means that for Ezekiel, Job was one of those mythological characters that people told stories about throughout the Near East, and not particularly Jewish, just as a story of a Noah-like character appears in the Epic of Gilgamesh, and a mythical Daniel is known from the ancient Semitic city of Ugarit.
In fact, archaeologists have uncovered quite a few written tales from the ancient Near East about gods punishing a completely upright man: they could be equivalent to Job in some ways, or even be the origin of the story. Such stories dating from as early as 4,500 years ago have been found in ancient Egyptian, Akkadian and Sumerian.
It is likely that in the very cosmopolitan world of the Persian period - sometime between 550 to 350 BCE - a Jew, living anywhere from Egypt to Palestine and Babylonia, whose mother tongue was Aramaic, - took one of these oral legends and wrote it in Hebrew. Who exactly he was we cannot know, but considering he wrote a book, he was probably a scribe.