摩訶止觀 7.131

7.131

修身戒心慧不可盡，名「欲無減」。慈悲度人，安住寂滅，不增不減，名「精進無減」。無量劫為一切眾生受苦，不疲不厭，名「念無減」。此三法是四種道品中八種精進也。

Cultivating the body, morality, mind, and wisdom inexhaustibly is called "zeal does not diminish". Compassionately delivering people while abiding securely in quiescent extinction without increase or decrease is called "vigour does not diminish". Undergoing suffering for all sentient beings throughout immeasurable kalpas without fatigue or revulsion is called "mindfulness does not diminish". These three dharmas are the eight kinds of vigour in the four kinds of the factors of the path.