瑜伽論記 10.495

10.495

難行慧三者，一、明證理甚深以明難；二、能知有情調化方便以明難；三、約智境無礙以明難。

As for the three wisdoms difficult to practice: first, it clarifies the difficulty by means of realizing the profound principle; second, it clarifies the difficulty by means of being able to know the expedients for subduing and transforming sentient beings; third, it clarifies the difficulty in terms of unhindered wisdom and its objects.