ANSWER: What few people realize is that the English phrase 'Holy Bible' does not occur anywhere in the KJV translation, even though the word 'holy' itself occurs more than 600 times. The closes Greek equivalent to 'bible' is the word biblia, which simply means 'books.'
The New Testament refers to the Old Testament writings in several ways. In the King James translation, the O.T. books are called "the scriptures" (John 5:39, Romans 15:4), the 'holy scriptures' (2Timothy 3:15, Romans 1:2) and the 'oracles of God' (Hebrews 5:12, Romans 3:2).
What it is and is not
The apostle Paul tells us in 2Timothy 3:16 - 17 that the purpose of God's word is multi-faceted. It teaches us sound doctrine, reveals our faults, flaws and sins, corrects us and then instructs us how we should live our lives ('instruction in righteous'). It contains information directly inspired by God that humans could NEVER discover on their own. As such, it imparts true knowledge and the means by which humans and God can be reconciled through Jesus Christ. It leads us to be a perfect man or woman of God that has the ability and skills to fill their lives with good works. All this ultimately leads to receiving salvation, as God's gift, in the resurrection and living forever as a spirit being.
The scriptures are not, and makes no claim to be, a comprehensive work of history (either religious or secular) or even of the lives of those found within its pages (e.g. Abraham, David, etc.). It is also, amazingly, not meant to be a comprehensive record of Jesus' entire life and ministry, as the apostle John wrote that there were MANY miracles, works and pieces of information regarding Christ he choose not to include in his gospel (John 21:25).
Since many folks understand that God is holy, but never wonder exactly why he or the Bible is so, we need to define the word. The word itself comes from the Hebrew kodesh (Strong's Concordance #6944). Kodesh signifies something consecrated, and is usually applied to a place considered sacred or to anything set aside for a sanctified purpose. The meaning of the word becomes a bit clearer in the Greek. The word holy is Hagios (Strong's #40), which means something that is blameless or pure.
Something designated as being holy must be sanctified or dedicated to being blameless or pure. To be pure or blameless, the thing, place or Being must be perfect and without any flaws. It must also be complete within itself. An item with this designation would contain no mistakes. Since God is holy (1Samuel 2:2, etc.) anything he sanctifies or dedicates is also designated as such.
The Bible is holy because God himself has sanctified or consecrated its words. All its books, though written by several imperfect people over a time period of more than 1,500 years (Job wrote the first book in the 1660's B.C. and John wrote the last book around 95 A.D.), were directly inspired by the Almighty. They were, in a sense, secretaries of the Eternal. The Bible is justifiably given this designation (2Timothy 3:15) because it reveals divine spiritual knowledge directly from our perfect and loving Creator.