瑜伽論記 21.464

21.464

言行自性，有三行差別者，景師云：身口意上生等行別在行蘊中，亦可三善根為三行，亦可三不善根為三，或三學為三行。今解：即身口意三業也。

Regarding "the intrinsic nature of activity (saṃskāra) has three distinctions of activity": Master Jing says that the distinctions of arising activity and so on on body, speech, and mind are located within the aggregate of formations; alternatively, the three wholesome roots are the three activities; alternatively, the three unwholesome roots are the three; or the three trainings are the three activities. Now I explain: they are the three karmas of body, speech, and mind.