I believe that Augustine actually said this centuries before any Sufi said it.

William Barto

Indeed, Augustine said something very much like this in de Trinitate, Book VIII, Chapter x. The argument goes on for some time and is characteristically complex, but it does begin there.

Micah Jackson

A Unitarian on the Trinity:

"Now I know I’ve just introduced another trinity into a unitarian church, and you can throw this threesome out with the same resounding thump the last one got booted with. But I beg you to remember that this is just a formulation, not an article of faith. This is just a way Hafiz and his company of King’s beggars, gamblers, scoundrels, divine clowns and astonishing fair courtesans - those royal rogues - reminded each other and us that this whole sacred game is not realized by directing all our attention out there somewhere. It is known here (pointing to heart), and here (pointing to between us all), as well as here (pointing to the sky.)
Make it a continuum rather than a trinity, for that is the point anyway. The point for us westerners, for whom the divine has always been predominantly external, is owning within ourselves the divinity we seek outside. As Ralph Waldo Emerson put it so well, “within us is the soul of the whole.”"
http://www.cedarlane.org/04serms/s041128.pdf
Title: God As Love, Lover, and Beloved