Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 15

Sanskrit:

बिभृयाच्चेन्मुनिर्वास: कौपीनाच्छादनं परम् ।त्यक्तं न दण्डपात्राभ्यामन्यत् किञ्चिदनापदि ॥ १५ ॥

ITRANS:

bibhṛyāc cen munir vāsaḥkaupīnācchādanaṁ paramtyaktaṁ na daṇḍa-pātrābhyāmanyat kiñcid anāpadi

Translation:

If the sannyāsī desires to wear something besides a mere kaupīna, he may use another cloth around his waist and hips to cover the kaupīna. Otherwise, if there is no emergency, he should not accept anything besides his daṇḍa and waterpot.

Purport:

A sannyāsī attracted to material possessions will spoil his worship of Lord Kṛṣṇa.