CC Madhya 9.259-260
arcanaṁ vandanaṁ dāsyaṁ
bhaktiś cen nava-lakṣaṇā
kriyeta bhagavaty addhā
tan manye ’dhītam uttamam
śravaṇam — hearing of the holy name, form, qualities, entourage and pastimes, all of which must pertain to Lord Viṣṇu; kīrtanam — vibrating transcendental sounds pertaining to the holy name, form, qualities and entourage, and inquiring about them (these also should be only in relationship to Viṣṇu); viṣṇoḥ — of Lord Viṣṇu; smaraṇam — remembering the holy name, form and entourage, and inquiring about them, also only for Viṣṇu; pāda-sevanam — executing devotional service according to time, circumstances and situation, only in relationship with Viṣṇu; arcanam — worshiping the Deity of Lord Kṛṣṇa, Lord Rāmacandra, Lakṣmī-Nārāyaṇa or the other forms of Viṣṇu; vandanam — offering prayers to the Supreme Personality of Godhead; dāsyam — always thinking oneself an eternal servant of the Supreme Personality of Godhead; sakhyam — making friends with the Supreme Personality of Godhead; ātma-nivedanam — dedicating everything (body, mind and soul) for the service of the Lord; iti — thus; puṁsā — by the human being; arpitā — dedicated; viṣṇau — unto the Supreme Personality of Godhead, Viṣṇu; bhaktiḥ — devotional service; cet — if; nava-lakṣaṇā — possessing nine different systems, as above mentioned; kriyeta — one should execute; bhagavati — unto the Supreme Personality of Godhead; addhā — directly (not indirectly through karma, jñāna or yoga); tat — that; manye — I understand; adhītam — studied; uttamam — first class.
“ ‘This process entails hearing, chanting and remembering the holy name, form, pastimes, qualities and entourage of the Lord, offering service according to the time, place and performer, worshiping the Deity, offering prayers, always considering oneself the eternal servant of Kṛṣṇa, making friends with Him and dedicating everything unto Him. These nine items of devotional service, when directly offered to Kṛṣṇa, constitute the highest attainment of life. This is the verdict of the revealed scriptures.’
Śrī Caitanya Mahāprabhu quoted these verses from Śrīmad-Bhāgavatam (7.5.23-24).