Authorship is primary:
In other words, the person writing had to be recognized as a true prophet of God.
This is important because prophets were understood to be the very mouthpiece of God. So when they spoke (or wrote) in an official capacity, it was understood they were speaking (or writing) God’s Words.
“A chain of verses in Chronicles gives us the tradition of a series of writing prophets in Israel. First Chronicles 29:29 says that the history of David was written in the books of the prophets Samuel, Nathan, and Gad. In II Chronicles 9:29 the history of Solomon is said to have been written by the prophets Nathan, Ahijah, and Iddo. In II Chronicles 12:15 the work of Rehoboam is said to have been written by the prophets Shemaiah and Iddo. Abijah’s history was added by Iddo (II Chron. 13:22); Jehoshaphat’s by Jehu the prophet, the son of Hanai (II Chron. 20:34); Hezekiah’s by Isaiah the prophet (II Chron. 32:32); Manasseh’s by unnamed ‘seers’ (II Chron. 33:19). The other kings are said to have their deeds recorded in the ‘book of the kings of Israel and Judah’ (II Chron. 35:27), although the names of the authors are not specified. We have listed here a chain of writing prophets from before the days of David to virtually the end of the kingdom of Judah. The old traditions of Israel preserved for us in the Books of Chronicles clearly include a succession of writing prophets.” (Harris, Inspiration and Canonicity of the Bible, pp. 166-67; cf. all of pp. 154-79).
The point is that Chronicles gives us a record of the method that was used in determining what was regarded as authoritative within the nation of Israel.
“Jesus, having all authority in heaven and on earth, delegated authority for ministry in history to his apostles. The head of the church commissioned and authorized them in his place to prescribe belief and action to the church. No longer mere learners, but apostles, they substituted for their King; witnessed to his life, death, and resurrection; served his purposes; and spoke for him with final authority . . . . The apostles, authorized by their Lord, ministered, not only in teaching and preaching, but also in writing. . . . New Testament books not written by apostles were written by apostolic associates and carry apostolic endorsement.” (Lewis and Demarest, 1:148-50).
In other words, the Apostles resume to role of NT prophet. Just as the OT prophets spoke the Word of YHWH, so the NT apostles are understood to be speaking the words of Christ.
1 Corinthians 14:37
“If anyone thinks he is a prophet or spiritual, let him recognize that the things which I write to you are the Lord's commandment.”
Paul is making the argument that if anyone is a true prophet, then they’ll be able to recognize his words as prophetically authoritative.
So in the OT, the words of a prophet were always to be tested (e.g., Deut. 13; Jer. 27).
In fact, this is why he goes on in 1Cor. 14:29 to say, “And let two or three prophets speak, and let the others pass judgment.” He’s picking up on this OT method for recognizing a true prophet. Their words were to be weighed.
The point, then, is Paul understood His own words to be prophetic, and therefore, authoritative.
So he’s challenging his readers, that if anyone is a true prophet, they’ll be known to be a true prophet (and how?) because they’ll recognize his words has authoritative.
Paul had that much confidence in his Apostolically derived authority.
2 Peter 3:15-16
“ Therefore, beloved, since you look for these things, be diligent to be found by Him in peace, spotless and blameless,15 and regard the patience of our Lord to be salvation; just as also our beloved brother Paul, according to the wisdom given him, wrote to you,16 as also in all his letters, speaking in them of these things, in which are some things hard to understand, which the untaught and unstable distort, as they do also the rest of the Scriptures, to their own destruction.”
Peter is equating the writings of Paul with the rest of Scriptures.
He understands them to carry Scriptural authority.
---- Reception History ----
(This is the study of how the church recognized what was authoritative. The key, here, is to know that the church didn’t give certain writings authority, rather the church had a process for recognizing what books contained authority.)
There were certain criteria that had to be met for a book to be seen as inherently authoritative.
Did the writer claim God was speaking through them?
Was the writer a prophet, or have prophetic endorsement?
Did the writings agree with previous doctrine?
In the OT, did the nation have a collective conscience that certain writings carried authority?
Did NT writers (or figures) quote the OT writing (e.g., Jesus quoting Jonah).
(1) Fancy theological terms for the history of reception.
Homologoumena — These are the writings accepted by all.
34 of the 39 Old Testament books were immediately accepted and 20-27 New Testament books were accepted.
Antilogoumena —Some books not immediately accepted. These books were regarded as authoritative a little later in history.
Old Testament: Song of Solomon, Ecclesiastes, Esther, Ezekiel, and Proverbs.
New Testament: Hebrews, James, 2 Peter, 2 John, 3 John, Jude, and Revelation.
Pseudepigrapha—Books unilaterally rejected by all as not from God.
Apocrypha—Books accepted by some.
“These books were never accepted by the Jews as scripture, but the use of the Apocrypha gradually increased in some parts of the church until the time of the Reformation. The fact that these books were included by Jerome in His Latin Vulgate translation of the Bible (completed in A.D. 404) gave support to their inclusion, even though Jerome himself said they were not “books of the canon” but merely “books of the church” that were helpful and useful for believers. The wide use of the Latin Vulgate in subsequent centuries guaranteed their continued accessibility, but the fact that they had no Hebrew original behind them, and their exclusion from the Jewish canon, as well as the lack of their citation in the New Testament, led many to view them with suspicion or to reject their authority. . . .There are doctrinal and historical inconsistencies with a number of these books. . . . It was not until 1546, at the Council of Trent, that the Roman Catholic Church officially declared the Apocrypha to be part of the canon. . . . It is significant that the Council of Trent was the response of the Roman Catholic Church to the teachings of Martin Luther . . . and the books of the Apocrypha contain support for the Catholic teaching of prayers for the dead and justification by faith plus works, not by faith alone.” (Grudem, Systematic Theology, pp. 57-59).
(2) The history of the Old Testament Canon.
The Old Testament was regarded as scripture as it was being written. Again, there was a collective conscience within the nation (and the leaders of the nation) as to what was authoritative.
Again, no one declared the OT authoritative, it was simply recognized as such. As we already mentioned, they’d ask questions, such as, is this a recognized prophet’s writing? Do their words contradict previous writings that were prophetic? etc.
(3) The history of the New Testament Canon.
The apostles were regarded just as authoritative as the Old Testament prophets (cf. 1 Corinthians 14:37). We saw Peter considering Paul to be as authoritative as the Old Testament (cf. 2 Peter 3:16).
As the New Testament was being written, it was being regarded as scripture, just like the Old Testament. We need to be careful that we do not place too much emphasis upon the human element in “deciding” what is canonical and what is not. The early church grasped what was authoritative and continued to hold to those books until finally in A.D. 397 the Council of Carthage affirmed what was already believed.
“Then the word of the LORD came to Jeremiah after the king had burned the scroll and the words which Baruch had written at the dictation of Jeremiah, saying, 28 "Take again another scroll and write on it all the former words that were on the first scroll which Jehoiakim the king of Judah burned.”
“Then the LORD answered me and said, "Record the vision And inscribe it on tablets, That the one who reads it may run.”
Lower (Textual) Criticisms
---- The Old Testament
There are less number of manuscripts then the NT, but the quality of those copies are of a much higher quality. This was due to very fastidious scribes.
“The manuscripts our translators use are generally so accurate that we can say that what those manuscripts teach, God teaches.” (Lewis and Demarest, Integrative Theology, 1:148).
---- The New Testament
There is a large number of manuscripts. Literally thousands. There is a much lower level of quality as a result. Some groups are found to be far more consistent than others.
Textual criticism “has to all intents and purposes recovered the original text of the New Testament.” George Eldon Ladd, The New Testament and Criticism [Eerdmans, 1967], p. 80.
“What the New Testament teaches, God teaches.”
(Lewis and Demarest, Integrative Theology, 1:154).