大般涅槃經集解 36.75

36.75

案僧亮曰：不能一日調伏心者，久脩慈者慈已成就，雖復經生暫忘修習，一日成就。「不從親起也」下諸譬，說瞋難除，明慈難成耳。

Sengliang states: As for 'not being able to tame the mind in a single day', for one who has long cultivated loving-kindness, loving-kindness is already accomplished; although passing through rebirths he may temporarily forget its practice, in a single day it is accomplished. The various similes from 'it does not arise from the intimate' downward explain that anger is difficult to eliminate, clarifying that loving-kindness is difficult to accomplish.