Only the spiritually fit person can spread Krishna consciousness by humbly serving the guru's mission.Listen — Srila Prabhupada Uvaca
Pradyumna: [chants verse, etc.] [break] yogya-pātra hao tumi bhakti pravartāite krame saba tattva śuna, kahiye tomāte [Cc Madhya 20.107] [00:20] Translation: "You are fit to propagate the cult of devotional service. Therefore gradually hear all the truths about it from Me. I shall tell you about them." Prabhupāda: Yogya-pātra hao tumi. This is hao not haoḥ. yogya-pātra hao tumi bhakti pravartāite krame saba tattva śuna, kahiye tomāte [Cc Madhya 20.107] So to propagate the devotional service of Kṛṣṇa consciousness, it requires the fit person.
Not that one can imitate. It is not possible. One who is fit to take this responsibility, he receives proper instruction and help from higher authorities. So Caitanya Mahāprabhu selected Sanātana Gosvāmī as the fit person, Sanātana Gosvāmī and Rūpa Gosvāmī.
They were ministers, but when Caitanya Mahāprabhu first met them in Rāmakeli, in Maldah district, at that time the..., one of the headquarters of Bengal government, so He thought... Not only He thought, but... These Caitanya Mahāprabhu associates, they are eternal associates. They appear somewhere...
Just like Haridāsa Ṭhākura appeared somewhere in Muhammadan family, Sanātana Gosvāmī was found engaged in government service, Raghunātha dāsa Gosvāmī was a zamindar's son. In different places. But actually they appear to fulfill the mission of Caitanya Mahāprabhu. Therefore they are called nitya-siddhas.
Just like Arjuna. Arjuna is nitya-siddha friend, eternal friend. Otherwise how Kṛṣṇa said that "Arjuna, when I spoke to sun-god..." Arjuna inquired that "Kṛṣṇa, how can I believe? Sun-god is long, long millions of years ago.
How it is that You taught him?" So what Kṛṣṇa replied? Kṛṣṇa said, "Yes, you were also present there, but you have forgotten. I have not forgotten." So similarly, whenever Kṛṣṇa goes anywhere, His eternal associates also go with Him. So sāṅgopāṅgāstra-pārṣadam. About Caitanya Mahāprabhu it is said in the Bhāgavatam, kṛṣṇa-varṇaṁ tviṣākṛṣṇaṁ sāṅgopāṅgāstra-pārṣadam [SB 11.5.32].
Saṅga, associates. Therefore we worship Caitanya Mahāprabhu with His associates. Śrī-kṛṣṇa-caitanya prabhu-nityānanda śrī-advaita gadādhara śrīvāsādi-gaura-bhakta-vṛnda. These are principal associates, and similarly other devotees of Śrī Caitanya Mahāprabhu, just like six Gosvāmīs and many others—we have got the list in the Caitanya-caritāmṛta—so they are all nitya-siddhas, eternal. There are two kinds of living entities: nitya-siddha and nitya-baddha.