成唯識論掌中樞要 2.124

2.124

有能中，謂於一切世、出世善，深信有力，能得、能成。《對法》但云：謂我有力，能得、能成。若准此解。其信二善，即得無為能成覺者，即信實有，信有用故，或信德攝，法中攝故。今又解云：信此二善，能得涅槃，能成大覺等。是信有能，有功能故。

Regarding 'having ability': it means having deep faith that one has the power to be capable of attaining and capable of accomplishing all worldly and supramundane wholesome [dharmas]. The Abhidharma merely states: 'It means [believing] that I have the power, being capable of attaining and capable of accomplishing.' If based on this explanation, believing in the two wholesomes, namely attaining the unconditioned and being capable of accomplishing awakening, is believing in real existence, because one believes in its utility; or it is subsumed under believing in virtues, because it is subsumed under dharmas. Now, another explanation states: believing that these two wholesomes are capable of attaining nirvāṇa, capable of accomplishing great awakening, and so forth, is believing in having ability, because there is efficacy.