The Coptic Church regarded the Old and New Testaments as a single inseparable unit. The basis of the Coptic version of the Old Testament is not a Hebrew text but the Septuagint. The Coptic Bible is based on Greek manuscripts that are older than most of the extant witnesses. However, the Coptic evidence has not yet been systematically applied to a textual criticism of the Greek Bible.
Manuscripts of the Coptic Bible are written in several dialects. The oldest extant Coptic biblical text is preserved in a manuscript of the Proverbs that dates from the late third century. A majority of scholars agree that both the New and Old Testaments must have already been translated from Greek into Coptic by the second half of that century.
We do not possess versions of all the books of the Old Testament. A considerable number of manuscripts from the fourth century provide evidence for the existence of larger or smaller portions of several Old Testament books written in the major Coptic dialects, except for the Lycopolitan. Apparently the entire Old Testament had been translated only in Sahidic, but that translation did not survive in its entirety. The Old Testament was also not completed in Boharic, but the following books have completely survived: the Pentateuch, Psalms, Job, the Minor Prophets, Isaiah, Jeremiah, Ezekiel, and Daniel.
Proverbs was partly translated. Joshua, Judges, 1-4 Kingdoms, 1-2 Chronicles, Wisdom of Solomon, and Sirach are attested only in liturgical passages. Ruth, Ezra, Nehemiah, Ecclesiastes, Song of Solomon, Esther, Judith, Tobit, and 1-2 Maccabees are not attested. The Psalms are best documented, for they played an important part in the liturgy and were learned by heart. There is not yet a complete critical edition of the Coptic Old Testament and no concordance for any dialect.
The Sahidic and Bohairic versions of the New Testament have been completely published by G. Horner (The Coptic Version of the New Testament in the Southern Dialect, 7 vols., Oxford 1911-1924; The Coptic Version of the New Testament in the Northern Dialect, 4 vols., Oxford 1898-1905). Horner’s edition of the Sahidic New Testament does not represent a homogeneous text, having been edited from many fragments with different dates and provenances. After the appearance of Horner’s edition, many manuscripts containing the complete Sahidic version of one of the New Testament books were published.
They range in date from the 4th or 5th century to the 10th century. Unlike the Sahidic version, there are a number of manuscripts containing complete books of the New Testament written in Bohairic that are unfortunately relatively late. Some manuscripts of other Coptic dialects have been published, such as the Subakhmimic (Lycopolitan) version of the Gospel of John, and the Gospel of Matthew in the Middle Egyptian dialect (Oxyrhynchus).