The Buddhist Practice of Loving Kindness (Metta)
The Theravadin scholar Acharya Buddharakkhita said of Metta,
"The Pali word metta is a multi-significant term meaning loving-kindness, friendliness, goodwill, benevolence, fellowship, amity, concord, inoffensiveness and non-violence. The Pali commentators define metta as the strong wish for the welfare and happiness of others (parahita-parasukha-kamana). ... True metta is devoid of self-interest. It evokes within a warm-hearted feeling of fellowship, sympathy and love, which grows boundless with practice and overcomes all social, religious, racial, political and economic barriers. Metta is indeed a universal, unselfish and all-embracing love."
Metta often is paired with Karuna, compassion. They are not exactly the same, although the difference is subtle. The classic explanation is that Metta is a wish for all beings to be happy, and Karuna is a wish for all beings to be free from suffering. Wish is probably not the right word, though, because wishing seems passive. It might be more accurate to say directing one's attention or concern to the happiness or suffering of others.
Developing loving kindness is essential to doing away with the self-clinging that binds us to suffering (dukkha). Metta is the antidote to selfishness, anger, and fear.
https://www.thoughtco.com/loving-kindness-metta-449703
