Our present material senses are blunt. By these present senses it is not possible to understand the transcendental nature of Kṛṣṇa, His name, His form, His quality, His pastimes. Everything of Kṛṣṇa, they are all divyam, divine. Janma karma ca me divyam (BG 4.9). So divyam, transcendental subject matter, is not possible to understand by these material blunt senses. Therefore one has to purify it. That is bhakti-mārga. Sarvopādhi-vinirmuktaṁ tat-paratvena nirmalam (CC Madhya 19.170). One has to purify the senses, and when the senses are purified, then, with that purified senses, hṛṣīkeṇa hṛṣīkeśa-sevanaṁ bhaktir ucyate. When our senses are purified, then we can serve Hṛṣīkeśa. Hṛṣīkeṇa hṛṣīkeśa-sevanam. Bhakti means to serve Kṛṣṇa, the master of the senses, by our senses. But these present senses, they cannot be fit for serving Kṛṣṇa. It has to be purified.
So how this purification is possible? Sevonmukhe hi jihvādau (Brs. 1.2.234): by engaging oneself in service of the Lord. And the first service begins from the tongue, jihvādau. We have got many senses, sense organs, but devotional service begins from the tongue, jihvā, jihvādau, by chanting. It is very difficult subject matter, but it is made easy because . . . Devahūti says, sukhaṁ buddhyeya: "Very easily I can understand, because I am woman." Kṛṣṇa is open to everyone: striyo vaiśyās tathā śūdrāḥ (BG 9.32). Although they are considered less intelligent, still, Kṛṣṇa is open to everyone. And especially in this age, kīrtanād eva kṛṣṇasya mukta-saṅgaḥ paraṁ vrajet (SB 12.3.51): "Simply by chanting Kṛṣṇa's name, this Hare Kṛṣṇa mahā-mantra," kīrtanād eva kṛṣṇasya mukta-saṅgaḥ, "one becomes liberated, and then paraṁ vrajet, he is transferred to the spiritual world."