This is part of the 10th Chapter of "A Bodhisattva's Way of Life" by Shantideva, written around 700AD. It is one of H.H., the 14th Dalai Lama's favorite dedications. It is often recited at the end of a meditation session to dedicate the merit accumulated during meditation to all beings everywhere. I find it most beautiful and it speaks to me deeply. It always warms my heart to say these words. I too find it the most wonderful of dedications. The book is also known as the Bodhicharyavatara.