In the first place, it would be natural that the habits of thought of the period when the Gospel was delivered orally should have continued to exert influence even after the tradition had been committed to writing.
It is essentially a book in the form of a discourse, whether it was ever orally delivered or not.
It was supposed that it had been handed down by Ezra; that it was indebted to Joshua, David or Solomon; that it was as old as Moses, to whom it had been communicated orally or in writing, complete or in its essence.
Besides definite works of this kind, there was also being formed during this period a large body of exegetical and legal material, for the most part orally transmitted, which only received its literary form much later.
Chairs had therefore to be founded under the title of rhetoric, from which men like Chrysoloras and Guarino, Filelfo and Politian expounded orally to hundreds of eager students from every town of Italy and every nation in Europe their accumulated knowledge of antiquity.
Substitutes may therefore be divided into those administered orally and those administered hypodermically.
The fullness and inaccuracy of detail which are a feature of the book suggest that Jason's information was derived from the recollections of eye-witnesses orally communicated.
The Judas legend, however, never really became popular, whereas that of Oedipus was handed down both orally and in written national tales (Albanian, Finnish, Cypriote).
The daily activities of the great mass of the adult population, in countries where commodities are sold at definite prices for definite quantities, include calculations which have often to be performed rapidly, on data orally given, and leading in general to results which can only be approximate; and almost every branch of manufacture or commerce has its own range of applications of arithmetic. Arithmetic as a school subject has been largely regarded from this point of view.
We cannot but suppose that at a time when the number of the original band of disciples of Jesus who survived must have been becoming noticeably smaller, and all these were advanced in life, the importance of writing down that which had been orally delivered concerning the Gospel-history must have been realized.