Secrets on Cultivating the Mind! (by Chinul, from the book Tracing Back the Radiance)
..."If you would understand your own mind, then without searching, approaches to the Dharma as numerous as the sands of Ganges would all be understood. As the World-Honored One said, "I see that all sentient beings everywhere are endowed with a tathagatha's wisdom and virtue." He also said, "All the illusory guises in which sentient beings appear take shape in the sublime mind of the Tathagatha's complete enlightenment." Consequently, you should know that outside this mind there is no buddhahood which can be attained."