The Greek original of canon(1) means primarily a straight rod or pole; and metaphorically, what serves to keep a thing upright or straight, a rule. In the New Testament it occurs in Gal. vi.16 and 2 Cor. x.13, 15, 16, signifying in the former, a measure; in the latter, what is measured, a district. But we have now to do with its ecclesiastical use. There are three opinions as to the origin of its application to the writings used by the church. According to Toland, Whiston, Semler, Baur, and others, the word had originally the sense of list or catalogue of books publicly read in Christian assemblies. Others, as Steiner, suppose that since the Alexandrian grammarians applied it to collections of Old Greek authors as models of excellence or classics, it meant classical (canonical) writings. According to a third opinion, the term included from the first the idea of a regulating principle. This is the more probable, because the same idea lies in the New Testament use of the noun, and pervades its applications in the language of the early Fathers down to the time of Constantine, as Credner has shown.(2) The "canon of the church" in the Clementine homilies;(3) the "ecclesiastical canon,"(4) and "the canon of the truth," in Clement and Irenaeus;(5) the "canon" of the faith in Polycrates,(6) the regula fidei of Tertullian,(7) and the libri regulares of Origen,(8) imply a normative principle. But we cannot assent to Credner's view of the Greek word for canon being an abbreviation of "Scriptures of canon,"(9) equivalent to Scripturae legis in Diocletian's Act(10) -- a view too artificial, and unsanctioned by usage.
It is true that the word canon was employed by Greek writers in the sense of a mere list; but when it was transferred to the Scripture books, it included the idea of a regulative and normal power -- a list of books forming a rule or law, because the newly-formed Catholic Church required a standard of appeal in opposition to the Gnostics with their arbitrary use of sacred writings. There is a lack of evidence on behalf of its use before the books of the New Testament had been paralleled with those of the Old in authority and inspiration.
The earliest example of its application to a catalogue of the Old or New Testament books occurs in the Latin translation of Origen's homily on Joshua, where the original seems to have been "canon."(11) The word itself is certainly in Amphilochius,(12) as well as in Jerome,(13) and Rufinus.(14) As the Latin translation of Origen has canonicus and canonizatus, we infer that he used "canonical,"(15) opposed as it is to apocryphus or secretus. The first occurrence of "canonical" is in the fifty-ninth canon of the Council of Laodicea, where it is contrasted with two other Greek words.(16) "Canonized books,"(17) is first used in Athanasius's 39th festal epistle. The kind of rule which the earliest fathers attributed to the Scriptures can only be conjectured; it is certain that they believed the Old Testament books to be a divine and infallible guide. But the New Testament was not so considered till towards the close of the second century when the conception of a Catholic Church was realized. The latter collection was not called Scripture, or put on a par with the Old Testament as sacred and inspired, till the time of Theophilus of Antioch (about 180 A.D.) Hence, Irenaeus applies the epithets divine and perfect to the Scriptures; and Clement of Alexandria calls them inspired.
When distinctions were made among the Biblical writings other words(18) were employed, synonymous with "canonized."(19) The canon was thus a catalogue of writings forming a rule of truth, sacred, divine, revealed by God for the instruction of men. The rule was perfect for its purpose.
The word apocryphal(20) is used in various senses, which it is difficult to trace chronologically. Apocryphal books are, --
1st, Such as contain secret or mysterious things, books of the higher wisdom. It is thus applied to the Apocalypse by Gregory of Nyssa.(21) Akin to this is the second meaning.
2nd, Such as were kept secret or withdrawn from public use. In this sense the word corresponds to the Hebrew ganuz.(22) So Origen speaking of the story of Susanna. The opposite of this is read in public,(23) a word employed by Eusebius.(24)
3rd, It was used of the secret books of the heretics by Clement(25) and Origen,(26) with the accessory idea of spurious,
4th, Jerome applied it to the books in the Septuagint which are absent from the Hebrew canon, i.e., to the books which were read in the church, the ecclesiastical ones(29) occupying a rank next to the canonical. In doing so he had respect to the corresponding Hebrew epithet. This was a misuse of the word apocryphal, which had a prejudicial effect on the character of the books in after-times.(30) The word, which he did not employ in an injurious sense, was adopted from him by Protestants after the Reformation, who gave it perhaps a sharper distinction than he intended, so as to imply a contrast somewhat disparaging to writings which were publicly read in many churches and put beside the canonical ones by distinguished fathers. The Lutherans have adhered to Jerome's meaning longer than the Reformed; but the decree of the Council of Trent had some effect on both. The contrast between the canonical and apocryphal writings was carried to its utmost length by the Westminster divines, who asserted that the former are inspired, the latter not.