If the Bible is God's word, or God's inspired word, that he went to a lot of trouble to give to the Hebrews, why did he not keep it straight afterwards?
There are multiple changes - as many as 40,000 according to scholars. Most are trivial mistakes due to careless copying. Some are due to difficulties in translation. Others are alterations to fit different groups ideas. Which means that the Bible we read today is different to the Bible that the people of 1000BC knew; different to 1000AD or 1500 or even 1900.
It's like the many religions - a maximum of 1 out of the thousands of versions can be correct. Either God doesn't think that it's important to keep the Bible authentic, or it's a human construct, vulnerable to all the changes that a human document might suffer.