I'm surprised at how quickly you divorce gestalt therapy from spirituality. I can quote quite a few authors who write specifically on this subject... Wilson Van Dusen, Joseph Zinker, Stella Resnick, Marc Joslyn, George Greaves, Claudio Naranjo... a whole book on the topic entitled "Body and Soul; Gestalt Therapy and religious experience" by James Walker... and some very interesting writing by Richard Hycner in Between Person and Person, particularly the chapter entitled The Spiritual Dimension in Psychotherapy. Let me offer you a quote....
"A dialogical psychotherapy is grounded in a broadly-based spiritual perspective. By no means does it subscribe to any particular religious beliefs, but rather assumes that all human dialogue is grounded in, and is an outgrowth of, a dialogue with Being."
Hycner, R. Between Person and Person, The Gestalt Journal Press, pg 91.