It is perfectly acceptable to submit letter of recommendations from spiritual leaders.  Often times they may know you the best second only to your family and are a good judge of character.  Make sure the letters focus solely on your involvement in the organization and community and not on any religious message per se.  Admissions committee members may not share your same beliefs but they can appreciate what your spiritual leader has to say about you since they are also community leaders in their own right.

Include specific details (i.e. length of activity, dates, etc.) about the projects you were involved with.

Did you teach sunday school? Include that to show that you can work well with kids.

Did you do community service outreach with your religious organization?

Include these details in a list and give it to your letter writer to help them add specific details of your contributions to the organization.