Yoga Sutra I:33
maitrī karuṇā mudito pekṣāṇāṁ sukha duhka punya āpunya visayāṇām bhāvanātaś citta-prasādanaṁ
To preserve the innate serenity of the mind, one should be happy for those who are happy, compassionate for those who are suffering, delighted for those who are virtuous, and indifferent towards the wicked.
Thinkyhead