In the beginning God created the heavens and the earth.
We tend to use books in order to guide us, to attain knowledge and more, in most chases non of us know the writer in person. The writer could have lived a 100 years ago, and we still will use the words he spoke through a book in order to gain wisdom.
But when it come to the bible we tend to challenge the authenticity of the book, just because it is beyond our own understanding. If however I read a book about science and do not understand what I read, I would not disregard the book on account of my own ignorance, would I. In the same way do not disregard God's Word on account of your own ignorance.
Paul said in 2 Timothy 3:16-17 Every Scripture is God-breathed and(or, Every writing inspired by God is) profitable for teaching, for reproof, for correction, and for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work.
We went to school not because we know everything, we went to school to be taught concerning things we do not know, to receive instruction concerning things attaining to life. For a school to be effective, the learners must attend the classes and receive what they are taught as if it is the truth. If only we would have the same approach to the bible the world would have been a better place.
There is a lot of reason given as to why the Bible is not God's Word, and most of the reasons is based on other document or myths concerning other older cultures, but all of it is based on what we believe to be true. To argue about the Bible as the Word of God, is like arguing against the mathematical principal that 1+1=2.