This verse asserts that whatever is considered as Scripture is breathed out by God. This means that if it is considered Scripture, it is to be taken as what God the Holy Spirit says through the vessel that He is using. It does not matter who the vessel is that He is using, whether it is a prophet, an apostle, a male or a female. This is done according 2 Peter 1:21 by the instrumentality of the Holy Spirit.
Peter thought that Paul’s words were equal to Scripture.
and consider that the longsuffering of our Lord is salvation—as also our beloved brother Paul, according to the wisdom given to him, has written to you, 16 as also in all his epistles, speaking in them of these things, in which are some things hard to understand, which untaught and unstable people twist to their own destruction, as they do also the rest of the Scriptures. – 2 Peter 3:15-16 (NKJV)
This is not an issue where context determines the understanding of whether or not it comes from the Lord. We believe that it comes from the Lord. Therefore, the context comes into play to understand the content of what God said through His vessel and how to apply that truth in our current context.
Now let’s look at some of Paul’s writings
These things I write to you, though I hope to come to you shortly; but if I am delayed, I write so that you may know how you ought to conduct yourself in the house of God, which is the church of the living God, the pillar and ground of the truth. – 1 Timothy 3:14-15 (NKJV)
Here Paul shares that the purpose of the letter he wrote to Timothy, his protege, was to show how church life was to be conducted according to the will of God not his own will.
Furthermore, when Paul shared something that he wholeheartedly believed came from the Lord but was not communicated by others he clearly stated that uniqueness.
Now to the married I command, yet not I but the Lord: A wife is not to depart from her husband. But even if she does depart, let her remain unmarried or be reconciled to her husband. And a husband is not to divorce his wife.
But to the rest I, not the Lord, say: If any brother has a wife who does not believe, and she is willing to live with him, let him not divorce her. – 1 Corinthians 7:10-12 (NKJV)
Then he also says by the Spirit at the end of this same passage in context:
But she is happier if she remains as she is, according to my judgment—and I think I also have the Spirit of God. – 1 Corinthians 7:40 (NKJV)
These words do not take away from the authority of the writing because even these words are inspired by God. These words show that the vessel being used was being carried, as Peter says, and were in complete control of their faculties as they wrote what the Lord would have them to write. This is why Peter could place Paul’s word on the same plane as the Scriptures themselves.
Let me address the religious leaders of Jesus’ day.
You search the Scriptures, for in them you think you have eternal life; and these are they which testify of Me. But you are not willing to come to Me that you may have life. – John 5:39-40 (NKJV)
They had the Scriptures but they misinterpreted them. Even in the time of Jesus the Sadduccess only believed in the 5 books written by Moses. The Pharisees believed in the Tanakh. The Tanakh is the Jewish collection of our 39 books of the Old Testament. Be careful! There is always a tendency to drift from truth when it does not fit into our frame of mind. Our duty today as believers and followers of Jesus is to understand the Scriptures, not question their authorship or authority. By faith we believe that what we have is entirely (plenary) in every word (verbally) given to the writers by God and is profitable for us today as the sufficient rule for faith and practice.
Now then, what is “all Scripture” that was referenced in 2 Timothy 3:16? Is it only the Scripture written before Jesus or are the New Testament writings included in Paul’s statement? I assert because of Paul’s use of the Lord’s statements that he knew that their writings were God’s words and God’s will for those who would believe.
I agree we must be careful. But our care must be in honoring the Word of God and clearly knowing what it is composed of as a whole. We cannot pick and choose. If Paul’s words are not Scripture then why would one believe that any of the New Testament was inspired by God? These words from Scripture cement my claim. I leave them with you.