Nāradaparivrājaka Upaniṣad 4.7

4.7

abhipūjitalābhāṃśca jugupsetaiva sarvaśaḥ |
abhipūjitalābhaistu yatirmukto'pi badhyate ||

That man who has jñāna as his staff is said to be the ēkaḍaṇdī (one having Brahman alone as the staff). An ascetic who, having merely a wooden staff without jñāna, eats all (indiscriminately) in all places, goes to the terrible hells called Mahāraurava. (The sense of) greatness in his case is likened by the ṛshis to the pig's dung. Having given it up, he should move about like a worm. Food and cloth without being begged for by him should be obtained involuntarily through the will of others. A naked (ascetic) may bathe at the wish of another. A man who practises the meditation upon Self in the dreaming state as in the waking is said to be the foremost and first of Brahmavāḍins. He should neither grieve for things not obtained, nor rejoice at things obtained. With the organs not attached to objects, he should be engaged in the sole protection of life. He should always look down upon the gains obtained with much respect (shown to him). Through the gains obtained with much respect, the ascetic though released becomes bound. What is meant by the protection of life, is this: When the fire (of the hearth in a house) had been extinguished and all have taken food, he may go to the houses of caste people that are fit for taking alms from. The yogin who has his hand only as his alms-bowl should not often take alms. He may take (food) standing or sitting; so in the middle (of taking food), he may sip water. Those who have pure mind should not over-step the limits like the ocean.