Quote from the above link:"I am going to end the agony.
It does not exist.
The poem...comes from a book called "The Gift: Poems by Hafez the Great Sufi Master" by Daniel Ladinsky, American Sufi poet. It was published in 1999 by Penguin Books and was commercially successful. However, this book has nothing to do with Hafiz. Ladinsky...doesn't even know how to read or write in Farsi. In fact, he claims that he has heard the poems from Hafiz himself in a dream...This has been rebuked by a lot of critics who accuse Ladinsky of out-right fraud and deception. Murat Nemet-Nejat, a modern Turkish essayist and poet, asserts "Ladinsky's book is an original poem masquerading as a translation... the book is worse than a failure; it is a deception, a marketing rip-off of his name".
The mystery is solved. There are no original Farsi versions of this poem. The verse that fascinated Mr. McGuinty so much actually comes from an American Sufi and his interpretation of "light"."