The meaning of 2 Timothy 3:16 hinges on the meaning of two words in that verse:
(theopneustos), "God-breathed, inspired by God"
This word occurs only once in the New Testament, in 2 Timothy 3:16. However, it is a compound of two common Greek words meaning "God" and "breath," so translating it is easy enough.
Exactly what the writer of 2 Timothy meant by it, however, is a matter of much debate among Christians, over many centuries. Various Christian theologians, denominations, and churches have come to different conclusions, in line with their views of the Bible and its inspiration. So there is no definitive answer; it is a matter of perspective.
However, in forming a view of the meaning of "inspired by God," it helps to know that our English words "breathe" and "inspire" reduce to only one word in the Biblical languages. If you wanted to say either "breath" or "inspiration" in Hebrew or Greek, you would use the same word.
Then the Lord God formed man from the dust of the ground, and breathed
into his nostrils the breath of life; and the man became a living
being. (Genesis 2:7)
This is usually interpreted to mean God literally breathed life into Adam. But it could also mean that God vivified Adam from God's spirit, which can be seen as the breath of life spiritually. Consider this incident in the New Testament:
When he [Jesus] had said this, he breathed on them and said to them,
"Receive the Holy Spirit." (John 20:22)
In this incident as written, Jesus physically breathed on his disciples (which is a little hard to picture), and in connection with that breathing invited them to receive the Holy Spirit.
It is unlikely that he literally meant that his breath was the Holy Spirit, and that his disciples were literally receiving the Holy Spirit as his breath touched their bodies. Rather, it is likely that Jesus meant his physical breathing on them to serve as a memorable physical image and metaphor of receiving the Holy Spirit--which is a spiritual and divine reality, not a physical one.
There is no way to state definitively what the writer of 2 Timothy meant by "God-breathed" or "inspired by God."
However, the example of God breathing into Adam's nostrils the breath of life so that he became a living soul, and the example of Jesus breathing on the disciples and inviting them to receive the Holy Spirit, suggests that inspiration when spoken of something that comes from God, such as the Bible (seen by Christians as "the Word of God"), means having life in it from God--especially spiritual life, which is the presence of the Holy Spirit, or the Spirit of Truth (see John 14:17; 15:26; 16:13; 1 John 4:6).
From this we can at least conclude fairly reliably that when the writer of 2 Timothy speaks of "God-breathed" or "inspired by God," he means that it contains the living spirit and truth of God.
(graphē), "Scripture, writing"
Unlike theopneustos, which occurs only once in the New Testament, graphe is a common word, occurring 51 times in the New Testament. It is related to the basic, common Greek verb meaning "to write." In its various forms and derivatives, this word occurs over 300 times in the New Testament. It is simply the common word for "writing."
The noun form graphe in the New Testament is almost always used to mean "Scriptures." For example:
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)
No New Testament canon had yet been adopted during the era in which the various books of the New Testament were written. The usual meaning for graphe, then, is the Old Testament scriptures, or Hebrew Bible.
The Old Testament canon
Even the Jewish canon, or Hebrew Bible, had not been fully settled by New Testament times. However, at a minimum the Torah, or "Law," which is the first five books of our Bible, was well-established at that time. And the Nevi'im, or Prophets was fairly well codified as consisting of:
- The Former Prophets: Joshua, Judges, 1 & 2 Samuel, 1 & 2 Kings
- The Latter Prophets: Isaiah, Jeremiah, Ezekiel, and the twelve Minor Prophets
These are almost certainly the books Jesus was referring to whenever he spoke of "the Law and the Prophets." However, Jesus also refers to Daniel as a prophet (Matthew 24:15), and in addition to quoting the Psalms several times as Scripture, in Luke 24:44 he explicitly includes the Psalms with "Moses" (the Law) and the Prophets as being written about him (prophetically).
So the Old Testament books that Jesus referred to the most, and gave the greatest weight to, were those contained in the Jewish Law and Prophets, plus Daniel and the Psalms.
The third division of Jewish scripture, the Ketuvim, or Writings, containing the rest of the books that are in the Protestant Old Testament (it does not include the Apocrypha), was not so clearly defined in New Testament times. Though they are referred to or alluded to at various places in the New Testament, they seem not to have carried the same weight that was given to the Law and the Prophets.
So when the New Testament refers to "the Scriptures," it is especially referring to the Law and the Prophets as defined in the Jewish canon, plus Daniel and the Psalms. These are the books that were given the greatest weight as Scripture in New Testament times.
Graphe in 2 Timothy 3:16 and 2 Peter 3:15-16
Since the New Testament canon had not yet been determined at the time that the various books of the New Testament were written, it is very unlikely that any of the writers of those books would have referred to them as "Scriptures" in the sense that we give to that word today.
In English, we are blessed with many words to refer to written materials.
In New Testament Greek, there are only one or two that are commonly used. One of them is graphe and related forms. The other is the word from which we get "epistle," which means a letter written to a person or group, very much the way we use the word in that sense today.
Because of this, the writers of the New Testament would have used the word graphe not only to refer to Scriptures as we understand them, but to refer to any written material as written material.
Most of the places where this word occurs in the New Testament, the meaning is not in question, because it is clearly referring to the Old Testament Scriptures as outlined above. That is the most likely meaning of "Scripture" in 2 Timothy 3:16.
However, there is one passage in the Epistles where, because of the context, it cannot mean only the Old Testament Scriptures:
So also our beloved brother Paul wrote to you according to the wisdom
given him, speaking of this as he does in all his letters. There
are some things in them hard to understand, which the ignorant and
unstable twist to their own destruction, as they do the other
scriptures. (2 Peter 3:15-16)
Christians, especially conservative Christians, commonly read this to mean that already at the time of the writing of 2 Peter the letters of Paul were being seen as Scripture. And by extension, putting this verse together with 2 Timothy 3:16, the traditional interpretation is that all of the books that are now included in our New Testament canon are stated to be "Scripture" and "inspired" or "God-breathed" by the New Testament itself.
However, this view is anachronistic. Once again, at the time that the various books of the New Testament were written, there was no set canon of books of the New Testament.
So there is no basis in statements made in the books of the New Testament themselves for the idea that the writer(s) of 2 Peter and 2 Timothy were saying, "All of the books that were later canonized as part of the New Testament are Sacred Scriptures and are inspired by God."
Most likely, graphe in 2 Peter 3:15-16 is being used in a broader sense to mean various writings that were being circulated among the early Christians. A modern way of saying this would be that he is referring to the then-existing body of Christian literature, which included various letters of Paul.
In 2 Timothy 3:16, on the other hand, the most likely meaning of graphe is the same as its meaning almost everywhere else in the New Testament: the Old Testament or Hebrew Scriptures.
Which books are most important?
Based on all of this:
- We can draw some reasonable conclusions from the New Testament about which books of Old Testament carried the greatest weight. Those books are the ones included in the Jewish Law and Prophets, plus the books of Daniel and Psalms. Lamentations could also be included as an extension of the book of Jeremiah.
- We cannot draw any strong and reliable conclusions from statements within the books of the New Testament about which books of the New Testament are inspired by God, or are the most important, or should be included in the Christian canon of Scripture. Historically speaking, those determinations fell to later Christian councils.