Scriptures not only teach what is true about salvation, they give salvation itself
10 You, however,… (that word however tells us that Paul is contrasting those who oppose the truth with Timothy… You, Timothy, unlike men who have opposed the truth and unlike those who have been disqualified regarding the faith…) have followed my teaching, my conduct, my aim in life, my faith, my patience, my love, my steadfastness, 11 my persecutions and sufferings that happened to me at Antioch, at Iconium, and at Lystra—which persecutions I endured; yet from them all the Lord rescued me. 12 Indeed, all who desire to live a godly life in Christ Jesus will be persecuted, 13 while evil people and impostors will go on from bad to worse, deceiving and being deceived. 14 But as for you, continue in what you have learned and have firmly believed, knowing from whom you learned it 15 and how from childhood you have been acquainted with the sacred writings (by the way… these sacred writings for Timothy were primarily the OT… not exclusively, but primarily…. this was an eye-popping experience for me when I first understood this some years back. This a-ha moment was one of those key moments in which God was burning down what I thought I understood about interpreting Scripture)… from childhood you have been acquainted with the sacred writings, which are able to make you wise for salvation through faith in Christ Jesus. 16 All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, 17 that the man of God may be competent, equipped for every good work.
Here is Paul’s will and testament for Timothy as Paul prepares to move into the pages of history: Unlike the unbelieving fools who oppose the gospel, Timothy is to continue in what he has learned and firmly believed from the “sacred writings” and then teach (2 Tim. 3:16,17) and preach (2 Tim. 4:1ff) what he has learned and firmly believed to others.
Timothy will be able to do this because the "sacred writings" that form the substance of what he is to pass along to others flow from the very creative life-breath of God. All scripture is God-breathed. This mention of breath calls to mind the breath of God that breathed life into Adam. This is the same breath that breathed life into Christ in the tomb. This is the same breath that breathed life into the church at Pentecost. This life-breath is being applied to the scriptures here in 2 Timothy 3. Since the scriptures come from the very life giving breath of God, they have the ability to provide saving life. These scriptures not only teach what is true about salvation, they give salvation itself. There is an innate ability of the scriptures, because they flow from the life-breath of God, to provide life. And it is through the God-breathed scriptures that one is regenerated and comes to saving faith in Christ Jesus (a thought that Paul also develops in Romans 10.)
Because these sacred writings flow from the very creative life-breath of God they are profitable and accomplish the four things mentioned in verse 15, which can be summarized as doctrine (orthodoxy - the content of belief that is in accord with the scriptures) and behavior (orthopraxy - practice that is in accord with scriptures). Paul's assumption is that right practice is impossible without right doctrine, and both flow from the original, creative life-breath of God. -- crb, Chapel sermon, "Wise for Salvation"