It is the short form of the maha-mantra, the great spiritual sound of final liberation:
Hare Krishna Hare Krishna Krishna Krishna Hare Hare
Hare Rama Hare Rama Rama Rama Hare Hare
“By vibrating this transcendental sound, the meaning of everything, both material and spiritual, is revealed. This Hare Krishna is nondifferent from the Personality of Godhead.” (from Bhaktivedanta Prabhupada Commentary, Srimad Bhagavatam 4.24.40)
What is the deeper meaning of the Hare Krishna mantra?
Caitanya Mahaprabhu teaches us that we should only beg God for His service life after life. This is the actual meaning of the Hare Krsna maha-mantra. When we are chanting Hare Krsna, Hare Krsna, Krsna Krsna, Hare Hare. Hare Rama, Hare Rama, Rama, Rama, Hare Hare, we are actually addressing God and His energy, Hara. Hara is Krsna’s internal potency, Srimati Radharani or Laksmi. Jaya radhe! This is daivi prakrti, and the devotees take shelter of the daivi prakrti, Srimati Radharani. Thus the Vaisnavas worship Radha-Krsna, Laksmi-Narayana and Sita-Rama. In the beginning of the Hare Krsna maha-mantra we first address the internal energy of Krsna, Hare. Thus we say, “O Radharani! O Hare! O energy of the Lord!” When we address someone in this way, he usually says, “Yes, what do you want?” The answer is, “Please engage me in Your service.” This should be our prayer. We should not say, “O energy of the Lord, O Krsna, please give me money. Please give me a beautiful wife. Please give me many followers. Please give me some prestigious position. Please give me the presidency.” These are all material hankerings, which should be avoided. Lord Buddha advocated that we give up all material desires. It is not possible to become desireless, but it is possible to give up material desires. It is the nature of the living entity to desire; it is not possible to be desireless. If one is desireless, he is dead. Desirelessness means purifying one’s desire, and desire is purified when we only desire the service of Krsna. (from “Teachings of Lord Kapila”)
Why is the Hare Krishna mantra so special?
Lord Krsna says in Bhagavad-gita (7.8), pranavah sarva-vedesu: ‘In all the Vedic mantras, I am represented by pranava, or omkara.’ Thus chanting of the Vedic mantras beginning with omkara is directly chanting of Krsna’s name. There is no difference. Whether one chants omkara or addresses the Lord as ‘Krsna’, the meaning is the same, but Sri Caitanya Mahaprabhu has recommended that in this age one chant the Hare Krsna mantra (harer nama eva kevalam). Although there is no difference between Hare Krsna and the Vedic mantras beginning with omkara, Sri Caitanya Mahaprabhu, the leader of the spiritual movement for this age, has recommended that one chant Hare Krsna, Hare Krsna, Krsna Krsna, Hare Hare. Hare Rama, Hare Rama, Rama Rama, Hare Hare. (from Bhaktivedanta Prabhupada Commentary, Srimad Bhagavatam 6.5.26)
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