The significance of the Old Testament: Monotheism leads to a single morality and a delineation of right versus wrong; laws and courts must be enforced by incorruptible judges.
The significance of the New Testament: Love and tolerance for enemies; the church and state have separate responsibilities.
From Princeton University, a survey of the origins and impact of each major version of the Bible.
Description (from MyJewishLearning.com, with summaries and descriptions of each chapter):
The Jewish Bible, or Tanakh, has three sections: Torah, Prophets, and Writings. But the Bible is hardly bound by its covers. It has inspired commentaries that span thousands of years. The origins of the biblical books may be disputed, but their centrality to Judaism–and Western civilization–is most definitely not. (More)
Complete text in English from Mechon-Mamre.org.
Description (from BooksOfTheBible.com, with summaries and descriptions of each chapter):
The New Testament is a collection of 27 books, usually placed after the Old Testament in most Christian Bibles. The name refers to the new covenant (or promise) between God and humanity through the death and resurrection of Jesus Christ. The New Testament chronicles the life and ministry of Jesus, the growth and impact of the early church, and instructive letters to early churches.
Complete text from Bartleby.com (see bottom of page), broken down by chapter, and searchable by word, chapter and verse.