As factually stated by Nanda Mahārāja, Garga Muni, being a devotee, had no needs. Similarly, when Kṛṣṇa comes He has no needs, for He is pūrṇa, ātmārāma. Nonetheless, He descends to this material world to protect the devotees and vanquish miscreants (paritrāṇāya sādhūnāṁ vināśāya ca duṣkṛtām (BG 4.8)). This is the mission of the Supreme Personality of Godhead, and devotees also have the same mission. One who executes this mission of para-upakāra, performing welfare activities for people in general, is recognized by Kṛṣṇa, the Supreme Personality of Godhead, as being very, very dear to Him (na ca tasmān manuṣyeṣu kaścin me priya-kṛttamaḥ (BG 18.69)). Similarly, Caitanya Mahāprabhu has advised this para-upakāra, and He has especially advised the inhabitants of India:
- bhārata-bhūmite haila manuṣya-janma yāra
- janma sārthaka kari' kara para-upakāra
"One who has taken his birth as a human being in the land of India [Bhārata-varṣa] should make his life successful and work for the benefit of all other people." (CC Adi 9.41) On the whole, the duty of a pure Vaiṣṇava devotee is to act for the welfare of others.
Nanda Mahārāja could understand that Garga Muni had come for this purpose and that his own duty now was to act according to Garga Muni's advice. Thus he said, "Please tell me what is my duty." This should be the attitude of everyone, especially the householder. The varṇāśrama society is organized into eight divisions: brāhmaṇa, kṣatriya, vaiśya, śūdra, brahmacarya, gṛhastha, vānaprastha and sannyāsa. Nanda Mahārāja represented himself as gṛhiṇām, a householder. A brahmacārī factually has no needs, but gṛhī, householders, are engaged in sense gratification. As stated in Bhagavad-gītā (BG 2.44), bhogaiśvarya-prasaktānāṁ tayāpahṛta-cetasām. Everyone has come to this material world for sense gratification, and the position of those who are too attached to sense gratification and who therefore accept the gṛhastha-āśrama is very precarious. Since everyone in this material world is searching for sense gratification, gṛhasthas are required to be trained as mahat, great mahātmās. Therefore Nanda Mahārāja specifically used the word mahad-vicalanam. Garga Muni had no interest to serve by going to Nanda Mahārāja, but Nanda Mahārāja, as a gṛhastha, was always perfectly ready to receive instructions from a mahātmā to gain the real benefit in life. Thus he was ready to execute Garga Muni's order.