CC Madhya 24.146

“ātmārāmāś ca api” kare kṛṣṇe ahaitukī bhakti
“munayaḥ santaḥ” iti kṛṣṇa-manane āsakti
Synonyms: 
ātmārāmāḥ ca api — self-realized persons also; kare — do; kṛṣṇe — unto Kṛṣṇa; ahaitukī bhakti — unmotivated devotional service; munayaḥ santaḥ — great saintly persons and transcendentalists; iti — thus; kṛṣṇa-manane — in meditation on Kṛṣṇa; āsakti — attraction.
Translation: 
“The six kinds of ātmārāmas render devotional service to Kṛṣṇa without ulterior motives. The words ‘munayaḥ’ and ‘santaḥ’ indicate those who are very much attached to meditating upon Kṛṣṇa.