CC Madhya 11.99

saṅkīrtana-yajñe tāṅre kare ārādhana
sei ta’ sumedhā, āra — kali-hata-jana
Word for word: 
saṅkīrtana-yajñe — in the performance of congregational chanting; tāṅre — unto Śrī Caitanya Mahāprabhu; kare — does; ārādhana — worship; sei ta’ — such a person; su-medhā — sharply intelligent; āra — others; kali-hata-jana — victims of this Age of Kali.
Translation: 
“Anyone who worships Lord Caitanya Mahāprabhu by congregational chanting should be understood to be very intelligent. One who does not do so must be considered a victim of this age and bereft of all intelligence.
Purport: 

Rascals propose that anyone can invent his own religious process, and this proposition is condemned herein. If one actually wants to become religious, he must take up the chanting of the Hare Kṛṣṇa mahā-mantra. The real meaning of religion is stated in Śrīmad-Bhāgavatam (6.3.19-22):

dharmaṁ tu sākṣād-bhagavat-praṇītaṁ
na vai vidur ṛṣayo nāpi devāḥ
na siddha-mukhyā asurā manuṣyāh
kutaś ca vidyādhara-cāraṇādayaḥ

svayambhūr nāradaḥ śambhuḥkumāraḥ kapilo manuḥ
prahlādo janako bhīṣmo
balir vaiyāsakir vayam

dvādaśaite vijānīmodharmaṁ bhāgavataṁ bhaṭāḥ
guhyaṁ viśuddhaṁ durbodhaṁ
yaṁ jñātvāmṛtam aśnute

etāvān eva loke ’sminpuṁsāṁ dharmaḥ paraḥ smṛtaḥ
bhakti-yogo bhagavati
tan-nāma-grahaṇādibhiḥ

The purport of these verses is that dharma, or religion, cannot be manufactured by a human being. Religion is the law or code of the Lord. Consequently religion cannot be manufactured even by great saintly persons, demigods or siddha-mukhyas, and what to speak of asuras, human beings, Vidyādharas, Cāraṇas, and so on. The principles of dharma, religion, come down in the paramparā system beginning with twelve personalities — namely, Lord Brahmā; the great saint Nārada; Lord Śiva; the four Kumāras; Kapila, the son of Devahūti; Svāyambhuva Manu; Prahlāda Mahārāja; King Janaka; grandfather Bhīṣma; Bali Mahārāja; Śukadeva Gosvāmī; and Yamarāja. The principles of religion are known to these twelve personalities. Dharma refers to the religious principles by which one can understand the Supreme Personality of Godhead. Dharma is very confidential, uncontaminated by any material influence, and very difficult for ordinary men to understand. However, if one actually understands dharma, he immediately becomes liberated and is transferred to the kingdom of God. Bhāgavata-dharma, or the principle of religion enunciated by the paramparā system, is the supreme principle of religion. In other words, dharma refers to the science of bhakti-yoga, which begins by the novice’s chanting the holy name of the Lord (tan-nāma-grahaṇādibhiḥ).

Therefore in this Age of Kali, as recommended here in the Caitanya-caritāmṛta (text 98), kali-kāle dharmakṛṣṇa-nāma- saṅkīrtana: the chanting of the holy name of the Lord is the method of religion approved by all Vedic scriptures. In the next text of the Caitanya-caritāmṛta, quoted from Śrīmad-Bhāgavatam (11.5.32), this principle is further stressed.