Rabindranath Tagore on the Upanishads

Though many of the symbolical expressions used in the Upanishads can hardly be understood today or are sure to be wrongly interpreted, yet the messages contained in these, like some eternal source of light, still illumine and vitalize the religious mind of India. They are not associated with any particular religion, but they have the breadth of a universal soil that can supply with living sap all religions which have any spiritual ideal hidden at their core, or apparent in their fruit and foliage. Religions, which have their different standpoints, each claim them for their own support.

Rabindranath Tagore

(Source: from the Forward by Rabindranath Tagore to The Philosophy of the Upanishads by S. Radhakrishnan)