The Bhaṭṭācārya replied, “A person who has received but a small fraction of mercy from Śrī Caitanya Mahāprabhu can understand that He is Lord Kṛṣṇa. No one else can.
The saṅkīrtana movement can be spread by a person who is especially favored by Lord Kṛṣṇa (kṛṣṇa-śakti vinā nahe tāra pravartana). Without first obtaining the mercy of the Lord, one cannot spread the holy name of the Lord. One who can spread the Lord’s name is called labdha-caitanya in the words of Bhaktisiddhānta Sarasvatī. The labdha-caitanya is one who has actually awakened his original consciousness, Kṛṣṇa consciousness. The influence of the pure devotees in Kṛṣṇa consciousness is such that it can awaken others to become immediately Kṛṣṇa conscious and engage themselves in the transcendental loving service of Kṛṣṇa. In this way the descendants of pure devotees increase, and Lord Caitanya Mahāprabhu takes much pleasure in seeing the increase of His devotees. The word su-medhasaḥ means “sharply intelligent.” When one’s intelligence is sharp, he can increase the interests of common men in loving Caitanya Mahāprabhu and through Him in loving Rādhā-Kṛṣṇa. Those not interested in understanding Śrī Caitanya Mahāprabhu are simply material in their attempts at professional chanting and dancing for money, despite their supposed artistry. If one does not have full faith in Śrī Caitanya Mahāprabhu, he cannot properly chant and dance in the saṅkīrtana movement. Artificial chanting and dancing may be due to sentiments or sentimental agitation, but this cannot help one advance in Kṛṣṇa consciousness.
Caitanya-caritamrta Madhya-lila 11.102 purport by Srila Prabhupada