妙法蓮華經玄贊 9.156

9.156

釋名者，離危怖曰「安」，適身心為「樂」。威儀可軌、語言有則，心除諂慢之流，志蘊慈悲之品，緣涉靡輟名之為「行」。安樂是果，行是因義，安樂之行是依主釋。若修因時離諸危怖，適悅身心名安樂行，即持業釋。「行」通平、去，行此經時獲安樂故。

Explaining the title: Being free from danger and fear is called 'peaceful' (ān); suiting the body and mind is called 'pleasant' (lè). Demeanor serving as a model, speech having rules, the mind purged of currents of deceit and arrogance, the will harboring qualities of compassion, engaging with conditions without interruption—this is called 'practice' (xíng). Peace and joy is the result, while practice has the sense of the cause; 'practice of peace and joy' is a determinative compound (tatpuruṣa). If at the time of cultivating the cause one is free from all dangers and fears, delighting body and mind, it is called 'peaceful practice', which is an appositional compound (karmadhāraya). The character 'xíng' can be read in either level or departing tone, because when one practices this sūtra, one obtains peace and joy.