The sublime puṇya-karma is devotional service. Śravaṇaṁ kīrtanaṁ viṣṇoḥ smaraṇaṁ pāda-sevanam (SB 7.5.23). This is the topmost puṇya-karma. Because, as it is stated in the Bhāgavata, śṛṇvatāṁ sva-kathāḥ kṛṣṇaḥ puṇya-śravaṇa-kīrtanaḥ (SB 1.2.17). Simply if we hear about Kṛṣṇa, that is puṇya. Even you do not understand, do not take it very seriously, if we simply give aural reception to the words of Kṛṣṇa, that activity itself is puṇya. Puṇya-śravaṇa kīrtanaḥ.
So one who has got, I mean, advanced in hearing about Kṛṣṇa, that is the result of multiforms of multivarieties of pious activities. Vāsudeva-kathā-ruciḥ (SB 1.2.16). Vāsudeva-kathā-ruciḥ is the resultant action . . . kṛta-puṇya-puñjāḥ (SB 10.12.11). These words are used. Just like when the cowherds boys were playing with Kṛṣṇa, Śukadeva Gosvāmī said that, "These boys are kṛta-puṇya-puñjāḥ. Heaps of pious activities they have performed; therefore they have got this chance of playing personally with the Supreme Personality of Godhead."