Hearing and chanting (Śrimad Bhagavatam 7.5.23-24)

śrī-prahlāda uvāca

śravaṇaṁ kīrtanaṁ viṣṇoḥ, smaraṇaṁ pāda-sevanam

arcanaṁ vandanaṁ dāsyaṁ, sakhyam ātma-nivedanam

iti puṁsārpitā viṣṇau, bhaktiś cen nava-lakṣaṇā

kriyeta bhagavaty addhā, tan manye 'dhītam uttamam

Prahlāda Mahārāja said: Hearing and chanting(singing) about the transcendental holy name, form, qualities, paraphernalia, and pastimes of Lord Viṣṇu, remembering them, serving the lotus feet of the Lord, offering the Lord respectful worship with sixteen types of paraphernalia, offering prayers to the Lord, becoming His servant, considering the Lord one's best friend, and surrendering everything unto Him (in other words, serving Him with the body, mind, and words)—these nine processes are accepted as pure devotional service. One who has dedicated his life to the service of Kṛṣṇa through these nine methods should be understood to be the most learned person, for he has acquired complete knowledge.