According to the Westminster Confession of Faith, Scripture thinks of man as a covenant being. It tells us that man was originally placed on earth under the terms of the covenant of works. It informs us further that man broke this covenant of works and that God was pleased to carry through his aims with the covenant of works by means of the covenant of grace. Thus Scripture may be said to be the written expression of the provisions of God’s covenantal relationship with man. The Confession further sets forth the Protestant doctrine of Scripture under the four heads of its necessity, its authority, its sufficiency and its perspicuity.
The necessity of Scripture lies in the fact that man has broken the covenant of works. He therefore needs the grace of God. There is no speech or manifestation of grace in nature.
—Cornelius Van Til, Christian Apologetics, 2nd ed. (Philiipsburg, NJ: The Presbyterian and Reformed Publishing Company, 2003).