"All scripture is inspired by God, and is useful for teaching, for reproof, for correction, and for training in righteousness," we read in 2 Timothy 3:16. What did the writer mean? Or is it obvious?
In the first place, the sentence obviously does not refer to the rest of 2 Timothy, which hadn't yet been written. Scripture, when the word is used (and it is often used!) in the New Testament, refers to the Old Testament. "The scriptures" were made up of three parts. There were the five books of the Law, sometimes referred to just as "Moses". There were the Prophets, which were the books which we would call the historical books (Joshua through to 2 Kings), plus Isaiah, Jeremiah, Ezekiel and the twelve "minor" prophets (Hosea through to Malachi). And there were the Writings - which included such books as the Psalms, the Proverbs and Job, but also Daniel and the two books of Chronicles.
In Jesus' day, there was no agreed canon of scripture - no list of which of these "writings" should be taken seriously. It was partly this that led to the disputes between the Pharisees, who accepted all of the Old Testament as we know it, and the Sadducees, who accepted only the five books of the Law. Jesus and his followers certainly drew for their teaching on the whole of the Old Testament - they saw Jesus as "the son of man" in the light of the Psalms (8:4, for instance) and of Daniel (7:13) - and possibly other books we do not find in our Bibles today. (The Jews agreed their own canon at the beginning of the second century.)
But secondly, the writer asserts that all scripture is written "for our learning". The same claim is made by Jesus himself ("You search the scriptures because you think that in them you have eternal life; and it is they that testify on my behalf." (John 5:39), and in Acts (17:11-12) we find Paul making converts in Berœa because his listeners check in the Old Testament, and find that what he has said agrees.
This is what our passage is saying - we can find sound and useful teaching in the Old Testament, but only if we can see it in a Christian light. Throughout Luke's account of the spread of the gospel, from the meeting with Jesus on the Emmaus road, through the whole of the Acts of the Apostles, we find preachers explaining how to interpret the Old Testament, just as the Gospel writers add little asides: "This was to fulfil what was written." "For our learning", yes, but only if our eyes have been opened by faith.
And thirdly, the writer calls scripture "inspired". The Holy Spirit is at work - as Paul writes to the Galatians: "The scripture ... declared the gospel beforehand to Abraham, saying 'All the Gentiles shall be blessed in you'." (3:8) The scriptures are not just words in a book, they are a living message - God's message.
The early Christians also saw the writings in the New Testament as authoritative. 2 Peter 3:16 suggests that Paul's writings already had authority, and in the course of time church leaders generally agreed on the current canon, with four Gospels, the letters of the apostles, and the Revelation, which was felt to be from the apostle John. (A few churches include other books, and at the Reformation an attempt was made to exclude such books as Hebrews and Revelation.)
By the Reformation, "scripture" was felt to include the Old and the New Testaments. And one of the mottos of the Reformation was sola scriptura - the scriptures alone were our guide to learning about God, just as sola fides - faith alone, was our guide to our relationship with God.
This led to a leap in Protestant scholarship. For if the Bible had to be stripped of the traditional interpretations that had been overlaid on it, it was necessary to analyze its original text more rigorously, to find out what it actually did say. Did God create plants before human beings (Gen 1:12) or after (Gen 2:5), was Joseph's father Jacob (Mat 1:16) or Heli (Luke 3:23), did God really ask Moses to commit genocide (Deut 7:2), was Jonah really swallowed by a big fish, how exactly did Jesus feed the five thousand, how many people went to the empty tomb?
This is a little different from the Anglican view, that "Holy Scripture containeth all things necessary to salvation: so that whatsoever is not read therein, nor may be proved thereby, is not to be required of any man, that it should be believed as an article of the Faith, or be thought requisite or necessary to salvation." Here, our faith comes first, and scripture confirms, supports and widens it.
The scriptures affirm our faith, and we should read them for the support they give. They allow God to speak to us, though they are not the only way that God can speak to us (as we recall when we sing the Gospel proclamation on Sundays - we live by every word that proceeds from God's mouth (Deut 8:3): something God's people were reminded of long before any scripture was set in writing!). They are a part of God's message, and one that we can carry with us, refer to, look at for comfort and guidance. Let us take them to heart!
HD