So, what was the Bible like to the earliest Christians? When the Bereans checked the Scriptures daily to verify what they were being taught (Acts 17: 10-12), what sort of Scriptures had they on hand to check? Since all copies were hand written onto scrolls, the books were scarce and public readings from them events worth attending. It was sort of like watching movies back in the mid-twentieth century. The only way to see them was in the movie theatre, when shown, and that was it, not like today when you can rent or purchase a recording of it and play it any time you please at home or even on the go. In Israel, the Jews often used the Scriptures in their original Hebrew/Aramaic versions, much as still used in synagogues to this day.
But over the preceding several centuries, Jews had undergone a significant change in the way they related to their Faith. Unlike any time before or since, the Jews became missionaries, spreading their faith into many far reaches of the known world. Not only did some Jews live in these areas, perhaps in search of better-paying jobs or for other reasons that for once Jews would come to live outside their homeland of Israel, but also there were unparalleled numbers of conversions to Judaism by the Gentiles. At the time it was seen as time for the seed of Abraham to begin blessing all the nations (Genesis 12: 2-3). Perhaps this was also seen as the time that anticipated the coming of the Messiah and, as St. John the Baptist preached, it was time to prepare the way of the Lord. It is for this reason that Jewish proselytes were frequently encountered in many lands during the early Church period.
One significant new evangelistic push on the part of the Jews was the translation, for the very first time, of their Scriptures into Greek, then the "lingua franca" used throughout the known civilized world. The result was a famous document known as the Septuagint. This translation of the Hebrew/Aramaic Bible took at least a couple centuries to complete, and with time rapidly assumed a near "inspired" status similar to the way the King James version is viewed in certain Protestant circles. Even some Jews in Israel used it, though many more continued to use the original Hebrew/Aramaic.
In preparing this Greek edition of the Bible, the Jewish three-tier approach for organizing the books seems to have been abandoned in favor of a more chronological arrangement, with the Law (which contains much history including the very earliest) and historical books first, the poetic and wisdom books in the middle, and the prophetic books at the end. For this reason one finds the book of Ruth directly after the book of Judges in Christian Bibles, since both were set in the same time. Such subtle points as the various tiers of Divine revelation were seen as confusing to proselytes and any other interested parties who just wanted to know the Scriptures, and a historical - poetical/wisdom - prophetic structure just seemed more understandable.
One of the bigger surprises one learns in going from having once been a Protestant and now being a Catholic is in learning that there really is no real gap between the Old and New Testament. The 66-book Protestant Bibles lack any books written after about 400 years before the birth of Christ, so to the Protestant it is as if God was silent for all that time. I remember in my Protestant days that this gap struck me as rather strange and unaccountable, mysterious and senseless. Such a gap also serves to heighten the differences between Judaism and Christianity, making them look even more unlike each other than they really are, and only all the more difficult to see the continuity between them (though undeniably there are differences). But of course the period was anything but silent, as regards Scriptural words of God. Books continued to be written for the Jewish Bible clear up to and even slightly past the First Century, and a few of these books finally came to be recognized as Sacred Scripture. These books (and yet others) were included in current copies of the Septuagint as found and used by the Apostles in their preaching and in preparing the New Testament texts.
It is possible that at least some of these newer books were originally written in Greek instead of either Hebrew or Aramaic, though a Hebrew text of Ecclesiasticus is known, as are Hebrew or Aramaic fragments of several other such books. As the use of Hebrew for worship came to be limited to many (but not all) Jews in Judea, but the Greek used by a majority of Jews around the world, relatively few Hebrew or Aramaic copies of these books were ever prepared, and some may well have been originally written in Greek by foreign Jewish Proselytes. Yet these books were incorporated into the Septuagint and as such used by and available to the earliest Apostles and Christians. Nearly all of them have since been accepted as canonical by the Church, though a few would be dismissed by the Church as apocryphal or else allowed to slip through the cracks.
The books of the Septuagint were as follows:
Obviously, there is no question here. These first five books are accepted by all.
4 I Kings (appears as I Samuel in most modern Bibles)
5 II Kings (appears as II Samuel in most modern Bibles)
6 III Kings (appears as I Kings in most modern Bibles
7 IV Kings (appears as II Kings in most modern Bibles)
8 I Paralipomenon (appears as I Chronicles in most modern Bibles)
9 II Paralipomenon (appears as II Chronicles in most modern Bibles)
10 I Esdras (which Jerome included in his Vulgate Old Testament as III Esdras but dismissed as apocryphal)
11 II Esdras (canonical, being the two Bible books Ezra and Nehemiah combined into a single book)
12 Esther (complete with the "additions")
15 I Maccabees
16 II Maccabees
17 III Maccabees (not now included in the Bible)
As one can see, the Septuagint included all the books dismissed by Protestants as "apocryphal" along with a few others likewise dismissed by the Catholic Church. But again bear in mind that such dismissal only deprives them of the status of "Sacred Scripture" but they must nevertheless retain value as documentary sources of Tradition, and as such are to be compared, one and all, as being on par with the writings of the Ancient Fathers, in terms of historic, moral, or doctrinal authority.
2 Psalm 151 (included in the Vulgate as "apocryphal")
3 Prayer of Manasseh (included in the Vulgate as "apocryphal," in one prominent Septuagint manuscript copy this slot contains a larger collection titled the "Odes," a collection of fifteen prayers/songs, of which the Prayer of Manasseh is the thirteenth)
7 Song of Solomon
8 Wisdom of Solomon
Psalm 151, being rather small and insignificant, seems to have fallen through the cracks. The Prayer of Manasseh is also listed as "apocryphal" by the Catholic Church but nevertheless was included in the official Latin Vulgate text. And again, note the last two books dismissed by Protestants as "apocryphal" though accepted as canonical by the Catholic Church. The fifteen prayers/songs that make up the Odes are: 1) First Ode of Moses (Exodus 15:1-19), 2) Second Ode of Moses (Deuteronomy 32:1-43), 3) Prayer of Anna, the Mother of Samuel (1 Kings (1 Samuel) 2:1-10), 4) Prayer of Habacuc (Habakkuk) 3:2-19), 5) Prayer of Isaiah (Isaiah 26:1-21), 6) Prayer of Jonah (Jonah 2:3-10), 7) Prayer of Azariah (Daniel 3:26-45), 8) Song of the Three Young Men (Daniel 3:52-88), 9) The Magnificat; Prayer of Mary the Theotokos (St. Luke 1:46-55), 10) Benedictus Canticle of Zachariah (St. Luke 1:68-79), 11) Canticle of Isaiah (Isaiah 5:1-9), 12) Prayer of Hezekiah (Isaiah 38:10-20), 13) Prayer of Manasseh, King of Judah when he was held captive in Babylon (ref. in 2 Chronicles 33:11-13), 14) Nunc dimittis; Prayer of Simeon (St. Luke 2:29-32), 15) Gloria in Excelsis Deo; Canticle of the Early Morning (some lines from St. Luke 2:14, Psalm 143:2 (144:2) and Psalm 117:2 (118:12)).
15 Baruch (chapters 1-5)
17 Letter of Jeremiah ("Baruch chapter 6")
19 Daniel (complete with the "additions")
This section mirrors exactly the selection of the relevant books for this category for the Catholic canon of Scripture, though again the Protestants dismiss Baruch, the Letter of Jeremiah, and the "additions" to the book of Daniel as "apocryphal." One interesting thing that occurs here is how the Greek rendered Isaiah 7:14, speaking of the mother of the Savior as "η παρθένος" (e parthenos), implying that she was the purified one, the consecrated virgin, whereas the original Hebrew had "הָ צַלָה" (ha `alma) which merely implies young maiden of no particular merit or accomplishment. Obviously the Jews who translated the Septuagint were anticipating a coming Messiah, to be born of a virgin, which prophecy the Messiah (Christ) actually fulfilled.
1 IV Maccabees (not included in the Bible)
2 Psalms of Solomon
3 II Esdras (apocryphal, sometimes appears as IV Esdras)
The fourth book of Maccabees was actually included at the end of the Septuagint as extent back then as an appendix, since it was seen even then as clearly apocryphal, yet still included as a part of it. The Psalms of Solomon are also sometimes found in the Septuagint, perhaps not as an appendix but somewhere else, and so must also be counted as part of it. IV Esdras was included in the Latin Vulgate as apocrypha, along with III Esdras, Psalm 151, and the Prayer of Manasseh. IV Esdras is the only book from that time which was not ever part of the Septuagint, and yet nevertheless included in the Latin Vulgate, albeit only as "apocrypha." The East Orthodox churches accept the Prayer of Manasseh, the apocryphal I (or III) Esdras, Psalm 151, the Odes, and III Maccabees as canonical.
In addition, several other books, though not included in any known copy of the Septuagint, were widely known to the First Century Apostles and Christians, or at least by the Ancient Fathers, occasionally (though only most rarely) quoted from authoritatively, and which known and ancient communities of Christians still accept as canonical, though the Catholic Church does not:
6 II Baruch "Letter of Baruch to the nine and one-half tribes" (Syriac II Baruch chapters 78-87)
7 IV Baruch
The book of Enoch (accepted by the Ethiopian Orthodox church as canonical) was quite explicitly quoted by St. Jude (14-15), and Jubilees (also accepted by the Ethiopian Orthodox church) is quoted by St. Paul in his letter to the Romans (2:29, 4:13, and 9:24). The "Letter of Baruch to the nine and one-half tribes (chapters 78-87 of the pseudepigraphical book of II Baruch) is accepted as canonical by the Syriac Orthodox church. IV Baruch is accepted as canonical by the Ethiopian Orthodox church.
And all of this brings us up to yet another group of "Old Testament related" books, called the Pseudepigrapha. Extant back in the First Century were these other books, such as the Ascension of Isaiah, the Assumption of Moses, the Testament of Abraham, the Life of Adam and Eve, the Apocalypse of Elijah, III Baruch (and the first 77 chapters of II Baruch), or Testaments of the Twelve and the like which were "scripture-like" in flavor (often similar to Ezekiel or the Revelation to St. John on Patmos), particularly of the prophetic books in terms of symbols and signs, though also embellishing known accounts from other Biblical episodes with (often fanciful) details.
These Pseudepigraphical books made no serious attempt at pretending to be inspired scripture, and yet were widely read and known, much as modern stories are known today. For example, many people in this day and age can say much regarding the details of legendary figures such as Darth Vader, Captain Kirk, Sherlock Holmes, or Perry Mason, yet of course we all know these "persons" have no real or literal existence except as literary figures. Because they were so commonly known, a number of these books were quoted (but only in the non-authoritative manner that a theologian could quote Star Wars or Star Trek or Sherlock Holmes or Perry Mason today to illustrate a point or provide a useful turn of phrase) in the pages of the New Testament. Given that a few of these books were even being written about the same time as the New Testament books themselves, it is even possible that some few of them actually quote the New Testament and not the other way around, for all anyone knows.
Because these books were mere fiction (some may even have been prepared by heretics of various sorts with a goal of using them to mislead souls, though many were probably written by uninspired amateurs showing forth their theological ignorance, but more commonly shying away from serious theology as they focused on legendary anecdotes and romances with an obvious appeal to artistic license), obviously one should not quote from them as though they were in any way Scripture, and yet ignorance of them causes any number of New Testament references to be unknown to modern readers in their original context which the various New Testament writers quoted them from.
I do think it is a serious mistake to disregard as though deliberately heretical those books either included in any prominent ancient codex or else accepted as canonical by any ancient congregation, apart from those books that show obvious signs of having been prepared specifically for them by referencing their specific and distinctive organizational structure, practices, founding heretical or schismatic leaders, or theological errors. The books I have listed above as being recognized by certain ancient Christian bodies are therefore different from the rest of the Pseudepigrapha and really should be regarded as something more akin to the regular apocrypha or to the writings of the early Fathers.
The rest of the Pseudepigrapha actually quoted in the New Testament or equally well known at the time might more properly fit in the third, or informational, category. Finally, those books that really are sectarian or heretical products should be regarded as "artifacts," something to know as deliberately erroneous or otherwise not pertinent to understanding the New Testament or to the actual Christian milieu of the First Century. Even here however, some of the errors condemned in Scripture (such as Gnosticism) are described in more detail in these heretical books, such as the Nag Hammadi texts, and as such of a certain limited value, at least to scholars who study the ancient heresies.
In balance, one should also remember that many books finally accepted as Scripture in the Old Testament were at one time or another challenged, or even doubted in certain circles for a season, notably the Song of Solomon, Ecclesiastes, Esther (as well as its "additions") Ruth, Proverbs, Ezekiel, Judith, Tobit, I Maccabees, II Maccabees, Wisdom of Solomon, Ecclesiasticus, Baruch, Letter of Jeremiah, the "additions" to Daniel, even as Ezekiel had also challenged before being accepted. Perhaps Esther, Ruth, and Baruch might well be in the Writings (Third tier) instead of the Prophets (Second tier) due to this doubt.