Mettā (Pāli) or Maitrī (Sanskrit) means unconditional and unattached loving kindness. It is one of the ten pāramitās of the Theravāda school of Buddhism, and the first of the four Brahmavihāras. The mettā bhāvanā (cultivation of mettā) is a popular form of meditation in Buddhism, practiced with mindfulness of breath, which provides concentration, so as to prevent the loss of compassion.
The object of mettā meditation is to cultivate loving kindness (love without attachment, non-exclusive love) towards all sentient beings. The practice usually begins with the meditator cultivating loving kindness towards themselves (though this is not specifically recommended by the Buddha himself in the relevant suttas/sutras), then their loved ones, friends, teachers, strangers and finally their enemies. It is a good way to calm down a distraught mind because it is an antidote to anger. Someone who has cultivated mettā will not be easily angered and can quickly subdue anger that arises. They will be more caring, more loving, and more likely to love unconditionally.
Buddhists believe that those who cultivate mettā will be at ease because they see no need to harbour ill will or hostility. Buddhist teachers may even recommend meditation on mettā as an antidote to insomnia and nightmares. It is generally felt that those around a mettā-ful person will feel more comfortable and happy too. Radiating mettā contributes to a world of love, peace and happiness.
Mettā signifies friendship and non-violence as well as "a strong wish for the happiness of others", but also less obvious or direct qualities such as showing patience, receptivity, and appreciation. Though it refers to many seemingly disparate ideas, Mettā is in fact a very specific form of love – a caring for another independent of all self-interest – and thus is likened to one's love for one's child or parent. Understandably, this energy is often difficult to describe in words; however, in the practice of Mettā meditation, one recites specific words and phrases in order to evoke this "boundless warm-hearted feeling." The strength of this feeling is not limited to or by family, religion, or social class. Indeed, Mettā is a tool that permits one's generosity and kindness to be applied to all beings and, as a consequence, one finds true happiness in another person's happiness, no matter who the individual is.
The full instructions for the theory and practice of mettā bhāvanā is available in the Visuddhimagga ("The path to purity"), Chapter IX, of the Buddhist scriptures.
The six stages of mettā bhāvanā meditation which are most commonly found involves cultivating loving-kindness towards:
For #2 avoid choosing someone that you feel sexually attracted to, or that is much younger or much older than yourself, or who is dead. For #3 choose someone that you might come in contact with every day, but who does not give rise to strong positive nor strong negative emotions. For #4 traditionally choose "an enemy", but avoid choosing a person who has just wrecked your life, unless you are very well grounded in awareness. For #5 treat them as equals, equally deserving of loving-kindness.
The Metta Meditation is attributed as words of the Buddha (Karaniya Metta Sutta, "Good Will", Sn 1.8):