Bhajana means these nine kinds of activities:
- śravaṇaṁ kīrtanaṁ viṣṇoḥ
- smaraṇaṁ pāda-sevanam
- arcanaṁ vandanaṁ dāsyaṁ
- sakhyam ātma-nivedanam
- (SB 7.5.23)
This is bhajan, bhajana-kriyā. Atho bhajana-kriyā. Ādau śraddhā tataḥ sādhu-saṅgo 'tha bhajana-kriyā (Cc. Madhya 23.14-15). Sadhu-sanga (CC Madhya 22.83). So mahat-sevā means sādhu-saṅga. If you associate with devotees, that is called sādhu-saṅga, mahat. Each devotee is mahātmā. And the signs are given there: mahat-sevāṁ dvāram āhur vimuktes mahāntas te sama-cittāḥ praśāntā (SB 5.5.2), we have already discussed. And another mahātmā is also ye vā mayīśe kṛta-sauhṛdārthā.
The main business is how far one is devoted to Kṛṣṇa. That is wanted. It doesn't mean that one has to become a sannyāsī or one has to remain a gṛhastha. There are four āśramas. You should accept whichever is suitable for you, but the business is how to serve Kṛṣṇa. That's if you find that remaining as a gṛhastha, you can serve more Kṛṣṇa, that's all right. Caitanya Mahāprabhu has accepted this. Sthāne sthitāḥ śruti-gatāṁ tanu-vāṅ-manobhir. Sthāne, sthāne means everyone has got some position. So it doesn't require that you have to change your position. But the real business is you have to see how far you are making progress in Kṛṣṇa consciousness.