大般涅槃經義記 5.303

5.303

問曰：慈心是無瞋性，云何斷貪？釋言：慈心正能斷瞋，傍能治貪，以不貪故，能捨己樂，惠施眾生，故能斷貪。經說修喜能斷嫉妬，今以何故說除不樂？兩言雖異，共成一義。若有嫉妬，見他得利熱煩不樂，由離嫉妬，故無不樂。

Question: The mind of benevolence has the nature of non-hatred; how can it eliminate greed? Answer: The mind of benevolence primarily eliminates hatred, and secondarily treats greed; because one is free from greed, one can renounce one's own happiness and bestow it upon sentient beings; therefore it can eliminate greed. The sūtra says that cultivating sympathetic joy eliminates envy; why is it now said to remove discontent? Although the two expressions differ, together they form a single meaning: if there is envy, seeing others gain benefit causes burning torment and discontent; by being free from envy, there is no discontent.