CC Madhya 25.83

muktānām api siddhānāṁ
nārāyaṇa-parāyaṇaḥ
su-durlabhaḥ praśāntātmā
koṭiṣv api mahā-mune
Word for word: 
muktānām — of persons liberated or freed from the bondage of ignorance; api — even; siddhānām — of persons who have achieved perfection; nārāyaṇa — of the Supreme Personality of Godhead; parāyaṇaḥ — the devotee; su-durlabhaḥ — very rare; praśānta-ātmā — completely satisfied, desireless; koṭiṣu — among many millions; api — certainly; mahā-mune — O great sage.
Translation: 
“ ‘O great sage, out of many millions of materially liberated people who are free from ignorance, and out of many millions of siddhas who have nearly attained perfection, there is hardly one pure devotee of Nārāyaṇa. Only such a devotee is actually completely satisfied and peaceful.’
Purport: 

This verse is quoted from Śrīmad-Bhāgavatam (6.14.5).