The easiest way to help you understand the spiritual underground is to ask you to first imagine the spiritual overground - the highly visible, well-intentioned and well-established network of churches, ministries and institutions that are the face of Christianity to our world.
In contrast, the spiritual underground is that hidden space, on the outskirts of Christendom, where unknown, unconventional and unlikely candidates do life and mission together in less-formal structures.
Historically, these misfits have been pioneers, who have contended for authenticity, honesty and original thought. In their passion to make a difference in the world, they have embraced praise and protest as being inextricably intertwined. Although their efforts have been a little scrappy, history has shown them to be surprisingly transformative. Their forward-thinking has triggered new ideas and given birth to new initiatives. Innovation in the underground has often resulted in the reformation of the overground.
Many bible stories show God instigating new stuff on the fringes of the established religious order. For example, the entrance of Jesus began with John the Baptist!
For the most part, the underground has tried to avoid labels. However, its proximity to the real world has typically resulted in a slightly more ‘edgy’ faith and a ‘gritty’ involvement in issues of social justice and the marginalized in society. The movement has preferred not to brand this activity as a ‘special interest’, but fundamentally human.