Anthroposophy is not a religion but an instrument for understanding religions

Anthroposophy is not a religion but an instrument for understanding religions. It’s related to religion in about the same way that our mathematical theory is related to ancient math books. One can understand mathematics out of one’s own intellectual forces and the laws of space without referring to Euclid’s geometry book. But when one has taken in geometric teachings one will treasure that old book all the more, that first placed these laws before the human spirit. That’s the way it is with anthroposophy. Its sources are not in documents and aren’t based on tradition. Its sources are in the real spiritual worlds; that’s where one must find them and grasp them in that one develops one’s spiritual forces, whereas one grasps mathematics as one tries to develop one’s intellectual forces. 

Source: Rudolf Steiner – GA 266 – From the Contents of Esoteric Classes: Esoteric Lesson – Berlin, 1903 or 1904