CC Madhya 8.70

kṛṣṇa-bhakti-rasa-bhāvitā matiḥ
krīyatāṁ yadi kuto ’pi labhyate
tatra laulyam api mūlyam ekalaṁ
janma-koṭi-sukṛtair na labhyate
Synonyms: 
kṛṣṇa-bhakti-rasa-bhāvitā — absorbed in the mellows of executing devotional service to Kṛṣṇa; matiḥ — intelligence; krīyatām — let it be purchased; yadi — if; kutaḥ api — somewhere; labhyate — is available; tatra — there; laulyam — greed; api — indeed; mūlyam — price; ekalam — only; janma-koṭi — of millions of births; sukṛtaiḥ — by pious activities; na — not; labhyate — is obtained.
Translation: 
“ ‘Pure devotional service in Kṛṣṇa consciousness cannot be had even by pious activity in hundreds and thousands of lives. It can be attained only by paying one price — that is, intense greed to obtain it. If it is available somewhere, one must purchase it without delay.’ ”
Purport: 

The previous two verses are included in the Padyāvalī (13, 14), an anthology compiled by Śrīla Rūpa Gosvāmī. Verse 69 refers to devotional service in faith, and verse 70 refers to devotional service rendered out of intense greed. The first is devotional service rendered in accordance with the regulative principles, and the second refers to spontaneous loving service of the Lord without extraneous endeavor. Henceforward the basic principle underlying the talks between Śrī Caitanya Mahāprabhu and Rāmānanda Rāya will be spontaneous loving service to the Lord. The regulative principles according to the injunctions of the śāstras are necessary insofar as one’s original dormant Kṛṣṇa consciousness is not spontaneously awakened. An example of spontaneous action is the flowing of rivers into the ocean. Nothing can stop this flow of water. Similarly, when one’s dormant Kṛṣṇa consciousness is awakened, it spontaneously flows to the lotus feet of Kṛṣṇa without impediment. Whatever will be spoken henceforth by Rāmānanda Rāya based on spontaneous love will be agreeable to Śrī Caitanya Mahāprabhu, and the Lord will ask him more and more about this subject.