When I occasionally quote the words of Jesus or the Buddha, from A Course in Miracles or from other teachings, I do so not in order to compare, but to draw your attention to the fact that in essence there is and always has been only one spiritual teaching, although it comes in many forms. Some of these forms, such as the ancient religions, have become so overlaid with extraneous matter that their spiritual essence has become almost completely obscured by it. To a large extent, therefore, their deeper meaning is no longer recognized and their transformative power lost.

Eckhart Tolle

from The Power of Now: A Guide to Spiritual Enlightenment