In the Babel of conflicting opinions, it is best to notice first the obvious internal phenomena. The first part of the Teaching (now distinguished as chaps. i.-vi.) sets forth the duty of the Christian; in chaps. vii.-x., xiv., we find a directory for worship; chaps. xi.-xiii., xv., give advice respecting church officers, extraordinary and local, and the reception of Christians; the closing chapter (xvi.) enjoins watchfulness in view of the coming of Christ, which is then described.
The amount of matter is not so great as that of the Sermon on the Mount.
The peculiarities of language are marked, but can only be indicated here in footnotes. They point to a period of transition from New-Testament usage to that of ecclesiastical Greek. The citations from the Scriptures resemble those of the Apostolic Fathers. The Gospel of Matthew is most frequently used, especially chaps. v.-vii. and xxiv.; but some of the passages fairly imply a knowledge of the Gospel of Luke. There are some remarkable correspondences with expressions and thoughts found in the Gospel of John, while there is good reason for inferring the writers acquaintance with all the groups of Pauline Epistles. His allusions to the other New-Testament books are less marked. There is nothing to prove that he did not know all of our canonical books. If an early date is accepted, the tone of the whole opposes the tendency-theory of the Tübingen school.
The most striking internal phenomena are, however, the correspondences of this document with early Christian writings, from a.d. 125 to the fourth century. With the so-called Epistle to Barnabas, chaps. xviii.-xx., the resemblances are so marked as to demand a critical theory which can account for them. A few passages in the Shepherd of Hermas show some resemblance; but only two sentences, in Commandment Second, are verbally the same. There is a still greater agreement with the so-called Apostolical Church Order, of Egyptian origin, probably as old as the third century. It is now known in the Coptic (Memphitic), and also in Arabic and Greek. 2361 The first thirteen canons correspond quite closely, both in order and words, with chaps. i.-iv. of the Teaching
Most noteworthy, however, is the parallel with the Apostolic Constitutions, vii. 1–32, which contain more than half the Teaching, in precisely the same order, with very close verbal resemblances. The parts omitted are in most cases such as had lost their pertinence in the fourth century, while they seem appropriate to a much earlier period. The details will be found in the footnotes to the Teaching in this volume. These phenomena have called forth voluminous discussions, and are the most important facts in determining the authenticity and age of the Teaching
The Church Order is to be distinguished from the Ethiopic collection of Apostolic canons; see Introductory Notice to Apostolic Constitutions.