Bhikshuka Upanishad of Shukla-Yajurveda

Among bhikṣus (religious mendicants) who long for mokṣa (salvation), there are four^[1] kinds, viz., Kuṭīcaka, Bahūdaka, Haṃsa, and Paramahaṃsa. Gautama, Bhāradvāja, Yājñavalkya, Vasiṣṭha and others belong to the first kind. They take eight mouthfuls (of food daily) and strive after mokṣa alone through the path of yoga. The second kind carry three (bamboo) staves (tied together) and a waterpot, and wear tuft of hair (śikhā), sacred thread (yajñopavīta) and red-coloured cloth. They take eight mouthfuls of food in the house of Brahmaṛṣis, abstain from flesh and alcohol and strive after emancipation alone through the path of yoga. Then the Haṃsas should live not more than a night in a village, five nights in a town, and seven nights in a sacred place, partaking daily of cow's urine and cow's dung, observing Cāndrāyaṇa^[2] and striving after mokṣa alone through the path of yoga. Paramahaṃsas like Samvartaka, Āruṇī, Śvetaketu, Jadabharata, Dattātreya, Śuka, Vāmadeva, Hārītaka and others take eight mouthfuls and strive after mokṣa alone through the path of yoga. They live clothed or naked at the foot of trees, in ruined houses, or in burning grounds. With them, there are no dualities as dharma and adharma, gain and loss, and purity and impurity. They look upon gold and stone and clod of earth with the same eye (of indifference), live on alms, begging from all without any distinction of caste and look upon everything as Ātmā alone. Being (naked) as nature made them, being free from the sense of duality and from covetousness, being engaged in pure contemplation (śukladhyāna), meditating on Ātmā, and begging at stated times, simply to keep the body and soul together, they reside in ruined houses, temples, straw-huts, ant-hills, the foot of trees, potteries, the places of agnihotra, the sand in the bed of rivers, mountain-caves, cavities, the hollows of trees, waterfalls, and sthaṇḍila (the level square piece of ground prepared for sacrifice). Having advanced far in the path of Brahman, and being pure in mind, they quit this body through the methods prescribed for Paramahaṃsa Sannyāsins. These are the Paramahaṃsas. Such is the Upaniṣad.