Avadhuta Upanishad reveals the highest form of Advaita Vedanta, generally taught to saṁnyāsins. This is because, a normal spiritual aspirant cannot understand its precepts, as it purely dwells on Nirguṇa Brahman. This is in the form of conversation between sage Sāṅkṛti and Bhagavān Dattātreya, who is the sixth incarnation of Lord Viṣṇu. Avadhūta means discarded; contextually it refers to the one, who has discarded all worldly feelings and obligations. Avadhūta Upaniṣhad comes under Kṛṣṇa Yajur Veda. Avadhūta Upaniṣhad is different from Avadhūta Gītā, though both are the teachings of Bhagavān Dattātreya.
Who is an Avadhūta? Bhagavān Dattātreya explains.
Avadhūta is the one who has immutable qualities; he is immutable because, he always dwells with Nirguṇa Brahman. He is beyond religions. There is nothing called good or bad for him. His behaviour will be totally different, uncaring for the society. He is like the sun, who vaporises both good and bad water. He experiences both good and bad things during his existence, but he never stays away from Nirguṇa Brahman. For him, there is no death and birth. Birth and death are for those who are afflicted with māyā; (the main work of māyā is to make a person deluded with duality, considering that the Self and the body are two different things.) Only those who are stricken by saṁsāra continue to be deluded by māyā, causing transmigration. Such persons perform various rituals to attain Liberation. But an Avadhūta is devoid of any actions such as sleeping or eating or bathing, etc. He is not concerned about his physical body. He is free from all sorts of doubts and fully aware of the Truth. He does not even meditate, as he is already aware of the Ultimate Truth. However, he has to undergo the effects of prārabdha karma (this means that he continues to live till he exhausts his prārabdha karmas, which he has acquired before realizing the Self). He has no confusions or contradictions and hence, he never meditates. The state of Avadhūta is beyond Jīvanmukta (Avadhūta has no inner movements (movement here means movement of his individual consciousness with Supreme Consciousness), as he is already with Brahman; in Jīvanmukta, this union though achieved, has to get fastened firmly). He always feels that he is Blessed and eternally remains in Blissful state.
The above is the essence of Avadhūta Upaniṣhad. There is Avadhūta Gītā, wherein Bhagavān Dattātreya reveals highest spiritual teachings. It has 289 verses classified under eight chapters. Discussion on Avadhūta Gītā is being taken up for discussion next.