ANSWER; (1) Matthew first made a record of the sayings of Christ without any reference to their historical setting. This so-called Logia was probably written from memory not many years after the Ascension. It is now generally believed that Mark several years afterwards gave these sayings their historical setting under the guidance of Peter, between A. D. 60 and 65. This makes Mark's Gospel the oldest. (2) All the Oriental teachers taught extemporaneously, expecting their disciples to remember without the aid of notes. After the Ascension, it was not thought necessary to write the Gospel immediately because they supposed that Christ would return during the lifetime of his Apostles. But his delay convinced them of the necessity of writing the precious words of the Saviour, lest, if left to tradition, they should be lost.
— Steele's Answers pp. 239, 240.