The Bible of Christian and Jewish scripture means simply that, “the book”. It's the definite article, not a book or one of the many competing books, it's the book. Almost everyone owns or has access to a copy or partial copy of the scriptures, for example people sometimes hand out free copies of the book of Psalms to passers-by. The Gideon Bible society has been placing a copy of the scriptures in hotels for visitors to read for over 100 years. The entire Greek and Hebrew scriptures are available for download and without charge. However much we have read for some of us the Bible is just too taxing, too complicated and even too voluminous a work to ever undertake reading the entire thing. That's where Bible commentaries can be helpful.
Commentaries composed by dedicated Bible scholars help us along in understanding difficult material which might otherwise take decades of study to learn without their input. They're often devotional, causing readers to see the importance and value of certain verses as they were understood by believers in the Christian and Jewish communities in the beginning.
People often call the Bible God's word because it's pages contain the spoken words of God. Yet there's something more. Over the course of fifteen hundred years God has done the work of inspiring prophets, apostles, great kings and humble fisherman to write the things He's prepared for them to share. For this reason people describe the Bible as God's word, because He's taken on the role of a superintendent.
Christian commentaries are a way of deepening our bond as spiritual people and coming together as a community to celebrate God's act of reaching down into history and doing something incredible. The incredible something is what we're going to read and find out about.
― Ty Cormack