The brahmavihārās (sublime attitudes, lit. "abodes of brahma") are a series of four Buddhist virtues and the meditation practices made to cultivate them. They are also known as the four immeasurables DN 13MN 43 (Sanskrit: apramāṇa, Pāli: appamaññā) or four infinite minds (Chinese: 四無量心).
The four Brahma Vihārās are four qualities that we cultivate in and out of meditation practice. They are qualities of the heart, offering a counterpart to the Buddhist insight practices. It’s often said that the mindfulness/insight practices are like one wing of a bird and the brahma viharas are like the other wing; a bird requires both wings to fly correctly. The brahma viharas, often referred to as the “heart practices”, are cultivated via specific meditation practices, but they also permeate our mindfulness and concentration practices.
Think of the four brahma vihārās, the four supreme emotions, loving-kindness, compassion, appreciative joy (joy with others), and equanimity. And see them, as the Buddha explained them, as the only emotions worth having. Nothing else has any real place in our hearts. And think your heart as yearning to be filled with love and compassion, with joy with others, and equanimity. See your heart as yearning for that and then fill it with those emotions. The warmth of love. The care of compassion. The generosity of joy with others. And the peacefulness of equanimity. Fill your heart to the brim.