成唯識論述記 6.58

6.58

述曰：自下破執。薩婆多說：要由有欲希望境力，諸心、心所方取所緣。若不希望，如何取境？即欲遍諸心，欲為諸法本，證欲遍義。

The Commentary states: From here below, refuting tenets. The Sarvāstivādins say: It is necessary that through the power of desire hoping for a sphere, the mind and mental factors can grasp their cognitive objects. If there were no hope, how could they grasp the sphere? Thus desire is omnipresent to all minds, and "desire is the root of all dharmas" proves the meaning of desire being omnipresent.