The Fourth Argument of Proclus the Successor

   

   Fourth. Each thing generated from a cause that is unmoved according to its substantial reality
   is unmoved. For if the maker is unmoved, he is unchanged, and if unchanged, then he produces
   by virtue of his very being, given that he shifts neither from making to not making nor from
   not making to making. For if he shifts, he will experience change in the very transition from
   the one to the other, and were he to experience change, he would not be unmoved. If therefore
   something is unmoved, it will either never make or always make; otherwise, whenever it does
   make, it would be moved. Consequently, if something unmoved is a cause of something, causing
   neither never nor sometimes, then it is always a cause, and if so, it is a cause of something
   eterna1.

   If the cause of the all is unmoved, - for were it moved, it would be earlier incomplete and
   later complete (since every motion is incomplete actuality) and furthermore would need time to
   bring time into being - then the all must be eternal, because it comes to be from an unmoved
   cause. Consequently, if someone, intending to pay respect to the cause of the all, should say
   that the cause alone is eternal and the cosmos is not eternal, then in saying the cosmos is
   not eternal, he asserts that its cause is moved rather than unmoved. By calling the cause
   moved rather than unmoved, he says it is not always complete but is at one time incomplete,
   because every motion is incomplete actuality and so needs something inferior (I mean time)
   because of its being moved; yet because he says it is sometimes incomplete and not always
   complete, i.e., needing something inferior, he in fact shows great disrespect.

   

   Proclus: On the Eternity of the World (De Aeternitate Mundi); Greek text with introduction,
   translation, and commentary by Helen S. Lang and A.D. Macro; University of California Press
   2001