大方廣佛華嚴經疏 37.20

37.20

第五、五力。即前五根增長，魔梵惑等不能屈伏，故名為力。又能損減不信等障，故復名力。《智論》云「能破煩惱，得無生忍，故名為力。」

Fifth, the five powers (bala): these are the preceding five faculties grown strong, such that Māra, Brahmā, defilements, and so forth cannot subdue them; hence they are called 'powers'. Furthermore, they are able to diminish obstacles such as lack of faith; hence they are also called 'powers'. The Mahāprajñāpāramitāśāstra says: 'Being able to destroy defilements and attain the endurance of the non-arising of dharmas, they are therefore called powers.'