Synesius, Dio 14
Synesius of Cyrene (c.370-c.413) was a Neo-Platonic philosopher who became bishop of Ptolemais in the Cyrenaica. He left behind a small corpus of texts that offer much information about daily life in Late Antiquity, and about the christianization of the Roman world.
In his speech Dio, named after Dio of Prusa, Synesius presents his cultural ideal. Paideia or general education (which means: study of the arts) is a preliminary or an initiation to philosophy, comparable to the development of Dio, who was (according to Synesius) a sophist first, but later converted to philosophy (which means knowledge of the Divine).
The text is offered here in the translation by A. Fitzgerald. The green four-digit numbers are page numbers of the Migne edition.
Synesius, Dio 14
  Now if you are annoyed with me, your father, because I have not corrected for you the manuscripts of Dio, the author who has led to so long a discussion, notice that neither have any other works of a similar nature been corrected for you, nor will Dio need a defense in this respect. Here again there will be need of rhetoric, but I will take my rule from philosophy. The name of Pythagoras of Samos, the son of Mnesarchus, has been inscribed upon the law, the law that does not permit us to make additions to books. On the contrary it demands that they should remain as first written, just as they once held their place in fortune or skill.
 In rhetorical speeches the law is that part which is not characterized by rhetoric, for it comes under the head of proofs that are not susceptible of argument, inasmuch as it strength resides, not in the persuasiveness of the speaker, but in the constitution of the state. And yet some of us claim to be orators on such a ground as this, though they are scribes pure and simple. Such men, even if they bring up witnesses in whose testimony the whole case really lies, will imagine that the favorable decision had been due to themselves; they are at the same time so clever and headstrong.
 Now, since it is not from the Twelve Tables of the Romans that we have read out the law, so as to make it authoritative even over those unwilling to accept it, but the word comes only from an ancient philosopher, some power of persuasion must needs be added and the speech thus becomes law. But lest we again unknowingly make a great statement about trifles (for in some way or other we are carried back from the lightest subjects to quite serious ones), we will then exercise all the precaution in our power, and if it is really necessary, we will take up some of the things that we have said, and if this is not enough, it would do well to take no additional trouble whatever about it.