Going through my notes for something I was researching years ago, I found the following quote:
Justice without religion is better for the order of the universe than the tyranny of a pious prince.
I had written down the book that I found it in, but not who originally said it. However, Google finds only one hit on that quote, and the attribution is to
Jami - presumably Nur ad-Din Abd ar-Rahman Jami (Persian: نورالدین عبدالرحمن جامی), it says on the Wikipedia page.
Update: The quote is indeed by Jami. The quote above is from the translation and abridgment of The Beharistan (The Abode of Spring) in
Four Sufi Classics, compiled by Idries Shah. The translation which includes the quote is by David L. Pendlebury.
I've recently discovered the treasure-trove that is
http://books.google.com/, and I see that they have
The Beharistan, translated by Richard Francis Burton, for free download. Nifty! I may update this with his take on the quote above at a later date.