Paramahamsa Upanishad 1
न दण्डं न शिखां न यज्ञोपवीतं न च कन्थां धारयेत् । शीतोष्णसुखदुःखमानावमानांश्च त्यक्त्वा
Na daṇḍaṁ na śikhāṁ na yajñopavītaṁ na ca kanthāṁ dhārayet, śītoṣṇa-sukha-duḥkha-mānāvamānāṁś ca tyaktvā
He should bear no staff, no tuft, no sacred thread, no patched garment — having abandoned cold and heat, pleasure and pain, honour and dishonour.