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.
Submission in Feeling
In the Skanda Purāṇa there is a statement by devotees praying to the Lord: "My Lord, I know that young girls have natural affection for young boys, and that young boys have natural affection for young girls. I am praying at Your lotus feet that my mind may become attracted unto You in the same spontaneous way." The example is very appropriate. When a young boy or girl sees a member of the opposite sex there is a natural attraction, without the need for any introduction. Without any training there is a natural attraction due to the sex impulse. This is a material example, but the devotee is praying that he may develop a similar spontaneous attachment for the Supreme Lord, free from any desire for profit and without any other cause. This natural attraction for the Lord is the perfectional stage of self realization.