ANSWER: What few people realize is that the English phrase "Holy Bible" does not occur anywhere in the KJV translation. In fact, the word Bible is not recorded anywhere in Scripture! The closest Greek equivalent to this word is biblia, Strong's Concordance #G975 and #G976, which simply means book or books.
In the Old Testament the word "holy," found at least 430 times in the KJV Bible, is primarily translated from either the Hebrew qodesh (Strong's #H6944), or qadosh (#H6918). These mean something that is sacred, sanctified or consecrated. In the New Testament, the word comes from hagios (Strong's #G40), which means something that is pure, blameless or consecrated.
The New Testament in the Bible refers to the Old Testament writings in several ways. In the King James translation, the Old Testament 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).
The apostle Paul tells us in 2Timothy 3:16 - 17 that the purpose of the Bible 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. It contains information directly inspired by God that humans could never discover on their own.
God's holy Bible imparts true knowledge to those who seek to understand it and the means by which reconciliation can occur through Jesus Christ. It leads us to be a perfect man or woman who has the ability to fill their lives with good works.
It should be noted that the Bible is 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.).
The Bible 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 (John 21:25).
Something designated as being holy must be 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 consecrated its words. All its books, though written by several imperfect people over a time period of more than 1,500 years, were directly inspired by the Almighty. They were, in a sense, secretaries of the Eternal.
In the final analysis, the Bible is justifiably called holy (2Timothy 3:15) because it reveals divine spiritual knowledge directly from our perfect and loving Creator.