Avatamsaka Sutra
As an early expression of Chan Buddhism, the "Inscription on Faith in Mind" reveals the Buddhist missionary use of expedient means (upaya) in China by adapting Taoist terminology to the Buddhist context of awakening. It also draws on the Wisdom sutras as well as the Avatamsaka Sutra and Lankavatara Sutra to express the essential unity of opposites and the basic nature of emptiness ("śūnyatā")