法界圖記叢髓錄 2.38

2.38

法記云：本願力者，佛修因時即發誓：念我當成佛，為三乘機施設教已，不令住跡，要必迴入一乘實體。如是起願也。法如是者，三世諸佛成正覺時，法爾如是起此願也。

Fa's Record states: As for 'the power of the fundamental vow': when the Buddha was cultivating the cause, he made the vow: 'Thinking, when I attain Buddhahood, having established the teachings for the capacities of the three vehicles, I will not let them abide in their traces, but will definitely have them return into the real substance of the One Vehicle.' He generated the vow in this manner. As for 'phenomena being thus': when the Buddhas of the three times attain right awakening, it is inherently thus that they generate this vow.