Iulianus Augustus: Oration VI - To the Uneducated Cynics; The Works of the Emperor Julian II,
   transl. W.C. Wright; Loeb 1913

   

   Further, that to make oneself like God as far as possible is nothing else than to acquire such
   knowledge of the essential nature of things as is attainable by mankind, is evident from the
   following. It is not on the score of abundance of possessions that we count the divine nature
   happy, nor on the score of  any other of those things that are commonly believed to be
   advantages, but it is because, as Homer says, "The gods know all things"; and indeed he says
   also of Zeus, “But Zeus was older and wiser." 

   For it is in knowledge that the gods surpass ourselves. And it may well be that with them also
   what ranks as noblest is self-knowledge. In proportion then as they are nobler than we in
   their essential nature, that self-knowledge of theirs is a knowledge of higher things.
   Therefore, I say, let no one divide philosophy into many kinds or cut it up into many parts,
   or rather let no one make it out to be plural instead of one. For even as truth is one, so too
   philosophy is one. But it is not surprising that we travel to it now by one road, now by
   another. For if any stranger, or, by Zeus, anyone of her oldest inhabitants wished to go up to
   Athens, he could either sail or go by road, and if he travelled by land he could, I suppose,
   take either the broad highways or the paths and roads that are short cuts. And moreover he
   could either sail along the coasts or, like the old man of Pylos, "cleave the open sea." And
   let no one try to refute me by pointing out that some philosophers in travelling by those very
   roads have been known to lose their way, and arriving in some other place have been
   captivated, as though by Circe or the Lotus-Eaters, that is to say by pleasure or opinion or
   some other bait, and so have failed to go straight forward and attain their goal. Rather he
   must consider those who in every one of the philosophic sects did attain the highest rank, and
   he will find that all their doctrines agree.

   Therefore the god at Delphi proclaims, "Know Thyself," and Heracleitus says, "I searched
   myself" ; and Pythagoras also and his school and his followers down to Theophrastus, bid us
   become like God as far as possible, yes and Aristotle too. For what we are sometimes, God is
   always. It would therefore be absurd that God should not know himself. For he will know
   nothing at all about other things if he be ignorant of himself. For he is himself everything,
   seeing that in himself and near himself he keeps the causes of all things that in any way
   whatever have existence, whether they be immortal causes of things immortal, or causes of
   perishable things, though themselves not mortal or perishable; for imperishable and
   ever-abiding are the causes of perpetual generation for the perishable world. But this line of
   argument is too lofty for the occasion.