The doctrine of the sufficiency of the Bible says that the Bible contains all the words of God that we need to know to be saved and to do His will and that it contains all the words of God that He intended people to have at each stage of redemptive history. These are the topics of the first and third sections of Chapter 8, “The Four Characteristics of Scripture: (4) Sufficiency,” of Wayne Grudem’s Systematic Theology, which my family and I are reading in our after breakfast Bible reading time. Between them is a section showing that we can find what God says about getting saved and doing His will. (Although I’ll share from all three sections here, we read just the first two in our family reading.) We expect to spend two or three more days reading from the chapter in our family reading.
That the Bible contains all the words of God that we need to know to be saved and to do His will is shown by Paul’s telling Timothy, “From childhood you have been acquainted with the sacred writings, which are able to make you wise for salvation through faith in Christ Jesus. All Scripture [the Old Testament and, in light of 1 Timothy 5:18, at least some of the New Testament] is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be competent, equipped for every good work” (2 Timothy 3:15-17, ESV; all Bible quotations are from the ESV).
Other Bible verses that show this are:
– “Blessed are those whose way is blameless, who walk in the law of the LORD!” (Psalm 119:1).
– “You have been born again, not of perishable seed but of imperishable, through the living and abiding word of God” (1 Peter 1:23).
That the Bible contains all the words of God that He intended people to have at each stage of redemptive history is suggested by His occasionally warning them not to add to what He’d already given to them. For example:
– “You shall not add to the word that I command you, nor take from it, that you may keep the commandments of the LORD your God that I command you” (Deuteronomy 4:2).
– “I warn everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues described in this book, and if anyone takes away from the words of the book of this prophecy, God will take away his share in the tree of life and in the holy city, which are described in this book” (Revelation 22:18-20).
Accepting the sufficiency of the Bible means that we can focus on the words of God in the Bible to find His will for us by collecting the passages in it relevant to the various aspects of Christian life, such as marriage. It also means that we can collect the passages in it relevant to doctrinal issues, such as the atonement. Various aids are available to help us collect passages on particular topics, including concordances, topical indexes, systematic theologies, and books on Christian life.
Here evangelical theologians differ from Roman Catholic and non-evangelical theologians. The former view the church’s official teaching throughout history as also being the words of God and so say that we should consider them too. The latter don’t view the Bible as being the words of God in an authoritative sense and so say that we should consider other early Christian writings as well as the Bible in determining what viewpoints Christians can hold. Evangelicals view the Bible as being the unique Word of God and thus say that we need and should consider only it.