瑜伽論記 6.400

6.400

解中，一、明觀待道理，云說名道理瑜伽方便者，如此觀待修瑜伽者，方便了知故立為觀待道理名瑜伽方便。

In the explanation: first, explaining the principle of dependence (apekṣā-yukti), where it says 'it is called the expedient means of yoga in principle': one who cultivates yoga in this way depending [on conditions] comes to know through expedient means, and therefore it is established as the principle of dependence and called the expedient means of yoga.