CC Madhya 15.131

raghunandanera kārya — kṛṣṇera sevana
kṛṣṇa-sevā vinā iṅhāra anya nāhi mana
Word for word: 
raghunandanera kārya — the duty of Raghunandana; kṛṣṇera sevana — worshiping Lord Kṛṣṇa; kṛṣṇa-sevā vinā — except for worshiping Kṛṣṇa; iṅhāra — of him; anya — other; nāhi — there is not; mana — intention.
Translation: 
“Furthermore, it is the duty of Raghunandana to always engage in Lord Kṛṣṇa’s service. He has no other intention but the service of Lord Kṛṣṇa.”