tomāra dui hasta baddha nāma-gaṇane
jala-pātra-bahirvāsa vahibe kemane
Translation: [Lord Nityananda to Lord Caitanya]: "Since Your two hands will always be engaged in chanting and counting the holy names, how will You be able to carry the water pot and external garments?"
Purport:
From this verse it is clear that Caitanya Mahāprabhu was chanting the holy names a fixed number of times daily. The Gosvāmīs used to follow in the footsteps of Śrī Caitanya Mahāprabhu, and Haridāsa Ṭhākura also followed this principle. Concerning the Gosvāmīs—Śrīla Rūpa Gosvāmī, Śrīla Sanatana Gosvāmī, Śrīla Raghunātha Bhaṭṭa Gosvāmī, Śrīla Jīva Gosvāmī, Śrīla Gopāla Bhaṭṭa Gosvāmī and Śrīla Raghunātha dāsa Gosvāmī-Śrīnivāsa Ācārya confirms:
saṅkhyā-pūrvaka-nāma-gāna-natibhiḥ. (Ṣaḍ-gosvāmy-aṣṭaka, 6) In addition to other duties, Śrī Caitanya Mahāprabhu introduced the system of chanting the holy name of the Lord a fixed number of times daily, as confirmed in this verse (tomāra dui hasta baddha nāma-gaṇane). Caitanya Mahāprabhu used to count on His fingers. While one hand was engaged in chanting, the other hand kept the number of rounds. This is corroborated in the Caitanya-candrāmṛta and also in Śrīla Rūpa Gosvāmī's
Stava-mālā:
badhnan prema-bhara-prakampita-karo granthīn kaṭīḍorakaiḥ
saṅkhyātuṁ nija-loka-maṅgala-hare-kṛṣṇeti nāmnām japan
(Caitanya-candrāmṛta, 9)
hare kṛṣṇety uccaiḥ sphurita-rasano nāma-gaṇanā
kṛta-granthi-śreṇī-subhaga-kaṭi-sūtrojjvala-karaḥ
(Caitanyāṣṭaka, 5)
Therefore devotees in the line of Śrī Caitanya Mahāprabhu must chant at least sixteen rounds daily, and this is the number prescribed by the International Society for Krishna Consciousness. Haridāsa Ṭhākura daily chanted 300,000 names. Sixteen rounds is about 28,000 names. There is no need to imitate Haridāsa Ṭhākura or the other Gosvāmīs, but chanting the holy name a fixed number of times daily is essential for every devotee.
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In the beginning of ISKCON Srila Prabhupada asked his American disciples to chant 64 rounds daily. But this was too much for them. So as a concession he reduced the number to 32 rounds. But this was still too much for them. So he reduced the required number of rounds to 16. Thus this 16 rounds was established by Srila Prabhupada as the minimum number of rounds required for every ISKCON devotee.
I hope this meets you in the best of health.
Your ever well-wisher,