The Bible is a book of history; a guidebook to live by; and, finally, God's written Word to the world. It is no wonder that many people cannot properly understand the Bible because it is a complex book and requires much study, even by those who love it. However, the primary reason many people cannot understand the Bible is that it is God's Word, and as such cannot be fully understood by the natural man.
Therefore, most people who want to use the Bible to support their points of view or to criticize the Bible are limited to just a few Scriptures that they think they understand. In most cases these Scriptures are not understood, and therefore taken out of context.
Throughout the Old and New Testament books of the Bible, the underlying theme is that Jesus Christ was the Messiah who was promised for the redemption of mankind. So if anyone wants to really understand the Bible, they must get to know Jesus Christ first. How do you do this? Find a church that has a pastor who preaches the sound doctrine of salvation as found in the Bible.