Isaiah - The miniature Bible

The Bible has 66 books. Isaiah has 66 chapters. The Bible has two Testaments: 39 books in the Old Testament, and 27 books in the New Testament. And, likewise, Isaiah has two parts: chapters 1 through 39 and then 40-66 giving us 39 and 27 chapters.
The emphasis of the 39 Old Testament books is on God's righteousness, Holiness and Justice and we see that same theme in chapters 1 through to 39 of Isaiah. The emphasis in the 27 books of the New Testament is on God's Glory, Compassion, and Grace; and again, we see that reflected in the final chapters of Isaiah.
The Old Testament emphasizes humanity's need for Salvation and chapters 1 through 39 of Isaiah emphasize Israel's need for Restoration.
In the New Testament, we see a description of God's provision of Salvation in the Messiah, and the chapters ending Isaiah 40-66 predict God's future Provision and
Salvation through the servant of God the Messiah.