三彌勒經疏 1.178

1.178

經曰「爾時迦葉去」以下，第二正答神變。此中二：先捨家標儀式、後正答神變。是初也。問：四威儀中皆得修善，何故偏說結坐？答：是賢聖常威儀，及順善品而不共外道故。正身者，即安坐義也。正意者正願，正願者是順善品義也。係念在前者，繫念念自面對義。何須對面者，無始時來男為女色、女為男色，多分依面故。今觀自面者，欲伏煩惱故。迦葉雖無煩惱，而遊觀大法故，作此坐儀也。

From the sūtra saying "At that time, Kāśyapa departed..." onward is the second part, directly replying regarding the miraculous transformations. Here there are two parts: first, renouncing the household life and marking the comportment; second, directly replying regarding the miraculous transformations. This is the first part. Question: One can cultivate good within all four postures of deportment; why is sitting cross-legged specified exclusively? Answer: It is the constant posture of deportment of the noble and worthy ones; it accords with wholesome factors, and it is not shared with non-Buddhists. "Upright body" means sitting stably. "Upright mind" means right resolve, and right resolve means according with wholesome factors. "Fixing mindfulness in front" means focusing mindfulness on the face opposite oneself. Why must one face [the face]? Because from beginningless time, men [lust] for women's beauty and women for men's beauty, mostly relying on the face. Now, contemplating one's own face is done to subdue afflictions. Although Kāśyapa was free of afflictions, because he surveyed and contemplated the great Dharma, he adopted this sitting posture.