Because the people of this age are so fallen, they can simply chant the Hare Kṛṣṇa mahā-mantra. In this way they can rid themselves of the bodily conception of life and become eligible to engage in the Lord’s devotional service. One cannot engage in the devotional service of the Lord without being purified of all contamination. This is confirmed in the Bhagavad-gītā (7.28):

yeṣāṁ tv anta-gataṁ pāpaṁ janānāṁ puṇya-karmaṇām
te dvandva-moha-nirmuktā bhajante māṁ dṛḍha-vratāḥ

“Persons who have acted piously in previous lives and in this life and whose sinful actions are completely eradicated are freed from the dualities of delusion, and they engage themselves in My service with determination.” Sometimes people are surprised to see young men and women take so seriously to the Kṛṣṇa consciousness movement. By giving up sinful activity — illicit sex, meat-eating, intoxication and gambling — and strictly following the injunctions given by the spiritual master, they have become purified of all contamination. They can therefore fully engage in the devotional service of the Lord.

In this Age of Kali, hari-kīrtana is very, very important. The importance of chanting the holy name of the Lord is stated in the following verses from Śrīmad-Bhāgavatam (12.3.51-52):

kaler doṣa-nidhe rājann asti hy eko mahān guṇaḥ
kīrtanād eva kṛṣṇasya mukta-saṅgaḥ paraṁ vrajet

kṛte yad dhyāyato viṣṇuṁ tretāyāṁ yajato makhaiḥ
dvāpare paricaryāyāṁ kalau tad dhari-kīrtanāt

“The most important factor in this Age of Kali, which is an ocean of faults, is that one can be free from all contamination and become eligible to enter the kingdom of God simply by chanting the Hare Kṛṣṇa mantra. The self-realization that was achieved in the Satya millennium by meditation, in the Tretā millennium by the performance of different sacrifices, and in the Dvāpara millennium by worship of Lord Kṛṣṇa can be achieved in the Age of Kali simply by chanting the holy names, Hare Kṛṣṇa.”