Theodor Zahn (1888): The original rule of Christianity commenced with Jesus Christ, his life, and his teachings. This was in line with the Jewish tradition to pass on and preserve authoritative religious books.

Adolf von Harnack (1925): The public reading of a book during worship should be distinguished from its inclusion in the canon. So therefore, the dating of the canon should be later, to the second century, to the time when N.T. texts are cited as Scripture.

Albert C. Sundberg Jr. (1968): “Scripture” and “canon” should be distinguished as termini technici in that “Scripture” refers to writings authoritative for religion, whereas “canon” refers to a collection, whose works are shown to be authoritative in relation to other books. The O.T. canon was defined only in the third century, leading Sundberg to believe that religious literature circulated freely, and canonization for the N.T. occurred much later.

Source: Craig D. Allert, A High View of Scripture?