Non-Catholics often point to 2Tim 3:16-17 as evidence for “sola Scriptura” (often times referred to as “SS” for short). And recently it was shown to me by someone as exactly such evidence for SS , stating that since Scripture says that Scripture makes us complete, that therefore “Scripture is fully sufficient and contains everything necessary that God wants us to know in terms of doctrine and theology…if something makes us complete, then we don’t need anything else”. He said that if we just look at the “plain language of the text”, we can see what Scripture is plainly telling us.
So, I looked at 2Tim 3:16-17 to make sure what he said is the same thing that Scripture says. 2Tim3:16-17 says, “All scripture is inspired by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be complete, equipped for every good work.”
By my questions to these types of claims are, “Where are you seeing Scripture ALONE? It looks to me that Scripture is “profitable”…“that a man…may be complete”. I do not see where it says that Scripture ALONE makes man complete all by itself. Where are you seeing that?"
I want to point out that nowhere does that verse (or ANY verse in Scripture) indicate that Scripture is the ONLY ingredient, so to speak, in what makes man complete…but that Scripture is profitable…that a man may be complete. And AMEN, by the way, Catholics believe that 100%! In the same line of thought, exactly as Paul is explaining it to Timothy, I can apply this to my physical person. Having an arm also makes me complete (physically), but does that mean that my arm, ALONE, makes me complete physically? No, it doesn’t. To be complete physically, I also need a head, a body, legs, the other arm… My arm is profitable…that I may be complete…but my arm is not the ONLY thing that makes me complete.
I also want to point out another critical point. If the language in 2Tim is evidence for “sola Scriptura”, then why isn’t James 1:4 evidence for “sola perseverance” (or endurance, or steadfastness…depending on the translation)? Let’s look at the passage in James and see what it says: “ My brothers and sisters, whenever you face trials of any kind, consider it nothing but joy,  because you know that the testing of your faith produces endurance;  and let endurance have its full effect, so that you may be mature and complete, lacking in nothing.” Verse 4 tells us, in an even more explicit language than found in 2Tim, that endurance (perseverance, steadfastness) makes us “complete, lacking in nothing”.
Now, no one believes that James teaches “sola perseverance”, (at least no one that I know of) but that’s the logical conclusion we have to come to if we say 2Tim teaches “sola Scriptura” based on the language used.
But, some may be very quick to point out something…even though Scripture says that endurance makes us complete, lacking in nothing, the “endurance” is only part of the picture…AND it flows from the testing of faith. So it isn’t the endurance ALONE that completes us. “AMEN!”, I say. But then they go on to say that, since the endurance flowed from a faith being tested…that it is the “faith that saves us”. More correctly, it is the” faith being tested”…or a “working faith” that saves us. That passage does not say ONLY that “faith produces endurance”, but “the testing of your faith produces endurance”. (And, AMEN to that…Catholics believe in salvation by faith!) But we must also not ignore the obvious here. Since we are saying that the plain language in 2Tim is evidence for “sola Scriptura”, we must look at the plain language here in James. James 1 does tell me that having my faith tested will produce endurance, but it also says that it is “endurance”, not faith, that makes me “complete, lacking in nothing”. So, according to James 1, what makes us complete…faith, or endurance? Scripture says “endurance” makes us complete. That is the plain reading of the text.
But, let’s take this reasoning provided for James, and apply it to 2Tim. The non-Catholic says that, even though Scripture says endurance makes us complete, that it is really what leads to endurance. Likewise, even though Scripture says Scripture can make a man complete, it is really what leads to Scripture.
2Tim says Scripture is “profitable…that a man may be complete”. So then, what REALLY makes the man complete? By the above reasoning, the answer would be whatever leads to Scripture. So what leads to Scripture…what is its source? Ultimately it comes from God…the Word of God…which Scripture tells us is not all written, but is actually a Person (cf. John 1), Who cannot be contained in a book (cff. John 1 and John 20:30, 21:25). So, 2Tim still does not teach “sola Scriptura” as was asserted and within that line of reason. It teaches “sola Word of God”, (AMEN!) which we know means more than what is written because the Word of God is more than what is written…He is a Living Person…the Christ…God.
But, in reality, that STILL isn’t what 2Tim is saying (even though it’s true that the Word of God, the Christ, makes us complete). 2Tim is saying exactly what it says, that “All scripture is inspired by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be complete, equipped for every good work”. And taken in proper context, Paul is actually only talking about the OT (the Septuagint, or Greek/Alexandrian Jews’ translation, to be exact)…because he is speaking of the Scriptures* that Timothy has "learned in [his] youth" (2Tim 3:1-17).**
If anyone claims 2Tim 3:16-17 for teaching “sola Scriptura”, by the very logic and reasoning they would use to support that claim, they must also logically conclude that James 1 teaches “sola perseverance”. Otherwise, they are being logically inconsistent. And always keep in mind that nowhere, ever, does Scripture make the claim that the ONLY Word of God we have been given is ONLY what is written in Scripture. In fact, Scripture explicitly and implicitly states the contrary (Lk 10:16, 2Thess 2:15, Jn 21:25, 2Tim 2:2, 1Pet 1:25, Rom 10:17, Mk 16:15, etc…cff. Mt 7:24, Mt 16:18, Jn 14:16, Mt 28:19-20, etc…).
And nowhere, ever, is there anything in Scripture that says or implies that what was passed down orally has ceased or been lost…leaving only what is written. Such a thought or belief [that the oral and Apostolic teachings have been lost, and the written Scriptures are all that are left] is a “tradition of man” (one that didn’t show up until AFTER the 1500’s) …and anyone claiming such should be called to task to provide their evidence, or explain why they think it is okay to believe this “doctrine of man”.
*, **(Incidentally...such reasoning as shown above for 2Tim and James 1:4 also contradicts the belief on "sola fide", or "salvation by faith alone"...because if Scripture makes us complete (in the "complete" sense that he was arguing for) and equipped for every good work, then what room is there for the "faith alone", which leads to good works? After all, I don't need faith to do those works if Scripture has already made me completely equipped for them, do I? “But WAIT!”, one might say. “2Tim says that Scripture makes you wise for salvation through faith…”. Yes, that’s right. It says, “ But as for you, continue in what you have learned and have become convinced of, because you know those from whom you learned it,  and how from infancy you have known the Holy Scriptures, which are able to make you wise for salvation through faith in Christ Jesus.  All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness,  so that the servant of God may be thoroughly equipped for every good work.” So, taken in context, 2Tim does not teach “sola Scriptura” at all, but “Scripture through faith in Jesus Christ”, which is neither “sola Scriptura”, nor “sola fide”. And as friend of mine points out, verse 14-15 speaks of oral instruction Timothy received. So taken together with v16 and 17...it is indeed not Scripture alone, but the oral teachings handed down to him, believed on the basis of whom it was that handed it to him, AND the Scriptures (Oral Tradition + Scripture, by the Authority of those who teach it) …just like the Bible teaches. The whole passage takes on another meaning when including verse 14-15.)