The sufficiency of Scripture means that Scripture contained all the words of God he intended his people to have at each stage of redemptive history, and that it now contains all the words of God we need for salvation, for trusting him perfectly, and for obeying him perfectly.
The necessity of Scripture means that the Bible is necessary for knowing the gospel, for maintaining spiritual life, and for knowing God’s will, but it is not necessary for knowing that God exists or for knowing something about God’s character and moral laws. -Wayne Grudem
These doctrines should not be hard to put together. If the Bible is truly the word of God, and if it is authoritative and sufficient for all life and godliness (2 Peter 1:3), then the Bible is necessary for the life of the Christian. When we read in 2 Timothy 3 that Scripture has been inspired by God and is useful for teaching, rebuke, correction and training in righteousness that the man of God might be equipped for every good work, we are reading Paul’s view of the sufficiency of Scripture. While the Bible doesn’t have a specific chapter and verse answer to every question we might ask, the Bible does provide everything we need for life and godliness. So, while the Bible might not tell you what job to get, it does tell you to work hard, as to please the Lord. While the Bible may not tell you to get up early, it does tell you not to be lazy. While the Bible might not tell us how we are to sing in church, it does tell us we are to sing psalms, hymns and spiritual songs.
If the Bible is sufficient, it only follows that it would be necessary for the Christian. We know that nature provides a testimony about God (Romans 1:18-20; Psalm 19:1-7), and we know that the moral law is present within the conscience of man (Romans 2:14-15), but we also know that those areas of testimony are not the gospel. The gospel (the good news of the kingdom of God coming in the person and work of Jesus Christ) is contained in the pages of Scripture.
How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching? And how are they to preach unless they are sent? As it is written, “How beautiful are the feet of those who preach the good news!” But they have not all obeyed the gospel. For Isaiah says, “Lord, who has believed what he has heard from us?” So faith comes from hearing, and hearing through the word of Christ. (Romans 10:14-17 ESV)
But as for you, continue in what you have learned and have firmly believed, knowing from whom you learned it and how from childhood you have been acquainted with the sacred writings, which are able to make you wise for salvation through faith in Christ Jesus. (2 Timothy 3:14-15 ESV)
The Bible is sufficient. There is a reason why the reformers held to Sola Scriptura and there is a reason why we hold to it as well:
- We reaffirm the inerrant Scripture to be the sole source of written divine revelation, which alone can bind the conscience. The Bible alone teaches all that is necessary for our salvation from sin and is the standard by which all Christian behavior must be measured.
- We deny that any creed, council or individual may bind a Christian’s conscience, that the Holy Spirit speaks independently of or contrary to what is set forth in the Bible, or that personal spiritual experience can ever be a vehicle of revelation.
Thanks be to God for his inspired, authoritative, clear, sufficient, necessary word.