In the First Canto, 5th Chapter, 22nd verse, of the Śrīmad-Bhāgavatam, Nārada Muni tells his disciple, Vyāsadeva, "My dear Vyāsa, you should know that persons who are engaged in executing austerities and penances, studying the Vedas, performing big sacrifices, chanting the hymns of the Vedas, speculating on transcendental knowledge and performing charitable functions have for all their auspicious activities simply to gain a place in the association of devotees and to chant the glories of the Lord." It is indicated here that chanting and glorifying the Lord is the ultimate activity of the living entity. Japa
When a mantra or hymn is chanted softly and slowly, that is called japa. The same mantra, when chanted loudly, is called kīrtana. For example, the mahā-mantra (Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare, Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare) when uttered very softly only for one's own hearing is called japa. The same mantra, when chanted loudly for being heard by all others, is called kīrtana. The mahā-mantra can be used for japa and kīrtana also. When japa is practiced it is for the personal benefit of the chanter, but when kīrtana is performed it is for the benefit of all others who may hear.
In the Padma Purāṇa there is a statement: "For any person who is chanting the holy name either softly or loudly, the paths to liberation and even heavenly happiness are at once open."
In the Skanda Purāṇa there is a statement about submission unto the lotus feet of the Lord. It is said there that those who are sober devotees can offer their submission to Kṛṣṇa in the following three ways: 1) samprāthanātmikā, very feelingly offering prayers; 2) dainyavodhikā, humbly submitting oneself; 3) lālasāmayī, desiring some perfectional stage. This desiring some perfectional stage in spiritual life is not sense gratification. When one realizes something of his constitutional relationship with the Supreme Personality of Godhead, he understands his original position and wants to be reinstated in this position, either as friend, servant, parent or conjugal lover of Kṛṣṇa. That is called lālasāmayī, or very eagerly desiring to go to one's natural position. This lālasāmayī stage of submission comes in the stage of perfect liberation, which is technically called svarūpa-siddhi, when the living entity understands, by perfect spiritual advancement and revelation, his original relationship with the Lord.