Most of us believe things because our churches tell us to believe them. We don’t want to be disobedient members of the church, so we say, “I believe,” as we do in the Nicene and Apostles’ Creeds. Mysticism is when God’s presence becomes experiential and undoubted. We can see a kind of courage and self-confidence in the mystics. That puts them in an extraordinary category. Mystics don’t say, “I believe.” They say, “I know.” A true mystic will ironically speak with that self-confidence but, at the same time, with a kind of humility. So, when we see that combination of calm self-confidence, certitude, and humility, all at the same time, we have the basis for mysticism in general. The only things we know at any deep and real level are the things we have personally experienced. Creedal belief, however, holds onto us until we have that experience! This is an important distinction and it is why we need creeds as well. Each generation and person cannot start at zero.
— from the book Yes, and...: Daily Meditations by Richard Rohr, OFM