大般涅槃經義記 6.374

6.374

身中，「慈悲」現化所因，「為眾苦行」隨物起化，「如著鬼魅」喻前慈悲，「狂亂多作」喻前苦行。

Regarding physical karma: "loving-kindness and compassion" are that upon which his manifestations depend; "undergoing austerities for the multitude" means giving rise to transformations in accord with beings. "Like being possessed by a demon" illustrates the former loving-kindness and compassion; "acting wildly in many ways" illustrates the former austerities.