The Catholic Encyclopedia defines religious quietism as:
…the doctrine which declares that man's highest perfection consists in a sort of psychical self-annihilation and a consequent absorption of the soul into the Divine Essence even during the present life. In the state of "quietude" the mind is wholly inactive; it no longer thinks or wills on its own account, but remains passive while God acts within it.
For the Catholic Church, this doctrine, which was banned, is a grave error or sin. It leads to “erroneous notions which, if consistently followed, would prove fatal to morality. It is fostered by Pantheism and similar theories, and it involves peculiar notions concerning the Divine cooperation in human acts.”
Yet it is difficult to see any of this dangerous material in “A Short Method of Prayer” by Jeanne Marie Bouvier de la Motte Guyon (1648-1717). Rather than being about “anything goes” and the abandonment of either religious or conventional morality, this book, and the quietism it expresses, is mild and inviting. By laying down your will, or parts of it, we invite the Divine into our formerly restless minds.
Of course, if you are running a church, want to fill pews, and fill up the collection basket, this kind of religious stance could be dangerous. But for the rest of us, quietism is a perfect way to enter into a relationship with the divine unhindered by organized structures, either spiritual or religious.