Compassion (Skt. karuna) is an important concept in Mahayana Buddhism. Compassion and wisdom are regarded as constitutive elements of a bodhisattva. It is out of compassion for all sentient beings locked in the eternal cycle of rebirth that a bodhisattva pledges not to enter nirvana before all beings have attained the ultimate truth.
«May all beings be free from hostility, free from oppression, free from fearfulness, may they live happily thereafter.»1
Sutrapitaka
1 Mettakatha: Patisambidhamagga II, 130, quoted after Alois Payer, Materialien zur buddhistischen Ethik, Lehrveranstaltung Ethik des Buddhismus, Univ. Tübingen, Ch. 6, Die vier unbegrenzten Haltungen, http://www.payer.de/buddhethik/ethbud08.htm, last accessed 24. 09. 2018, translation by NS.