CC Madhya 24.141
tvayy asta-bhāvād aviśuddha-buddhayaḥ
āruhya kṛcchreṇa paraṁ padaṁ tataḥ
patanty adho ’nādṛta-yuṣmad-aṅghrayaḥ
ye — all those who; anye — others (nondevotees); aravinda-akṣa — O lotus-eyed one; vimukta-māninaḥ — who consider themselves liberated; tvayi — unto You; asta-bhāvāt — without devotion; aviśuddha-buddhayaḥ — whose intelligence is not purified; āruhya — having ascended; kṛcchreṇa — by severe austerities and penances; param padam — to the supreme position; tataḥ — from there; patanti — fall; adhaḥ — down; anādṛta — without respecting; yuṣmat — Your; aṅghrayaḥ — lotus feet.
“ ‘O lotus-eyed one, those who think they are liberated in this life but are without devotional service to You are of impure intelligence. Although they accept severe austerities and penances and rise to the spiritual position, to impersonal Brahman realization, they fall down again because they neglect to worship Your lotus feet.’
This is a verse from Śrīmad-Bhāgavatam (10.2.32).