— Vine Deloria Jr.
Commonly attributed to Deloria on the internet, or sometimes to a few others, but without legitimate sourcing, the earliest variant of this yet located is a single quotation in Awakened India Vo. 99 (1994) p. 327, ascribed to Fr. Patrick Collins, University of Notre Dame, USA:
Religion is for those who are afraid of going to hell. Spirituality is for those who know they have been there — perhaps through involvement with religion.
The next variant located is ascribed to an anonymous member of Alcoholics Anonymous in Illuminating the Heart: Steps Toward a More Spiritual Marriage (1996) by Barbara G. Markway, p. 28:
Religion is for people who are afraid of going to hell; spirituality is for those who have been there.
A variant also occurs in The Higher Power of the Twelve-Step Program: For Believers & Non-Believers (2001), by Glenn F. Chesnut, Ch. 1 : Discovering a Higher Power:
Religion is for people who're afraid of going to hell; twelvestep spirituality is for those who've been there.