Answer:

I believe you should be extremely cautious in declaring that the Bible was the first to say that the earth is round.  How would you know this?  More than 99.99% of everything said or discovered by ancient man is lost.  How could we know whether someone in 2000 BC proposed that the earth was round, but it was not written down or perhaps this writing was later lost?

What we can say is that in Isaiah 40:22 we see the following words:  “He [ie God] sits enthroned above the circle of the earth.”   I will have to say that I find this passage really interesting and even inspiring in that it accurately describes the earth as circular.  However, I temper my enthusiasm for a couple of reasons.  First of all, the Hebrew word is circle, not sphere.  It is an ambiguous word.  As an analogy, we say that the earth is round.  Do we mean a flat circle or a sphere?  Of course, we mean spherical, but the word is ambiguous.  The fact is that many in the ancient world saw the earth as a flat circle.  If so, then the statement in Isaiah, using a somewhat ambiguous word which could be a sphere or a flat circle, is perhaps a bit less of a slam dunk as evidence for the inspiration of the Bible than some of us might wish.

By the way, as far as I know, the first recorded to have unambiguously claimed that the earth is in fact spherical was the Greek mathematician and philosopher Pythagoras in the 500s BC.  Isaiah was written in the 700s BC.  So, if Isaiah is in fact describing the earth as spherical (which is somewhat doubtful, but…) then it would be the first recorded statement to that regard.  However, we cannot know for sure is this is literally the first time this was said, only that it is the first record we have of this claim. Also, the word here is a bit ambiguous as to whether the earth is spherical or flat but round.  For this reason, I would not use Isaiah 40:22 as a really strong apologetic for the inspiration of the Bible, even though it is tempting to do so.

The original date for the writing of the Old Testament is an extremely complicated question.  Parts of it, such as Esther and Malachi, were written in the 5^th century BC.  Isaiah was written in the 8^th century BC.  Exodus through Deuteronomy were written either in the fifteenth or the thirteenth century BC, depending on which conservative scholar you talk to.  There are a number of issues here.  We cannot absolutely prove that Exodus through Deuteronomy were written at this early date.  In fact, some internal evidence points to an editor adding some small comments at a much later date.  Also, there are a number of parts of the Old Testament we really have little idea when they were written.  When was Job written?  Genesis is a difficult question as well.  It appears to have oral tradition from all the way back nearly 2000 BC, but we really have no idea when the oral tradition was written down.  Perhaps it was back in the time of Moses, perhaps earlier or perhaps later.  Some of the Psalms are by David and therefore from the eleventh century BC, but others are by Moses, the Sons of Korah, Asaph, and at least one is from the period of the exile (Psalm 126), which would be more than 500 years after David wrote his psalms.  Solomon probably wrote much of Proverbs, but certainly not all of it.  1 and 2 Samuel and Kings were written considerably earlier than 1 and 2 Chronicles, but we really do not know the dates.

Sorry, but you are going to have to live with a fair amount of ambiguity as to the dates of the writing of much of the Old Testament.  There are some books (Daniel, Ezra, Nehemiah) which we know with rather good precision, but there are others we really do not know the dates they were written.

John Oakes