SB 12.3.51

kaler doṣa-nidhe rājann
 asti hy eko mahān guṇaḥ
kīrtanād eva kṛṣṇasya
 mukta-saṅgaḥ paraṁ vrajet
Word for word: 
kaleḥ — of the Age of Kali; doṣa-nidheḥ — in the ocean of faults; rājan — O King; asti — there is; hi — certainly; ekaḥ — one; mahān — very great; guṇaḥ — good quality; kīrtanāt — by chanting; eva — certainly; kṛṣṇasya — of the holy name of Kṛṣṇa; mukta-saṅgaḥ — liberated from material bondage; param — to the transcendental spiritual kingdom; vrajet — one can go.
Translation: 
My dear King, although Kali-yuga is an ocean of faults, there is still one good quality about this age: Simply by chanting the Hare Kṛṣṇa mahā-mantra, one can become free from material bondage and be promoted to the transcendental kingdom.
Purport: 

After mentioning the innumerable faults of this Age of Kali, Śukadeva Gosvāmī now mentions its one brilliant aspect. Just as one powerful king can kill innumerable thieves, one brilliant spiritual quality can destroy all the contamination of this age. It is impossible to overestimate the importance of chanting Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare, especially in this fallen age.