Mahāyāna Mahāparinirvāṇa Sūtra
The "Tathagātagarbha Sūtra" constitutes one of a number of Tathāgatagarbha or Buddha-nature sutras (including the "Mahāyāna Mahāparinirvāṇa Sūtra", the "Śrīmālādevī Siṃhanāda Sūtra", the "Angulimaliya Sutra", and the "Anunatva-Apurnatva-Nirdesa") which unequivocally declare the reality of an Awakened Essence within each being.