瑜伽論記 14.45

14.45

但應隨定道俱思而立，測云：防護律儀中有二解。一解：即以善思及以五根名為防護，能護律儀故名律儀，體非律儀。又解：戒體所防護故名防護。

It should only be established according to the volition concurrent with concentration and the path. Ce says: In the restraint of guarding and protecting, there are two explanations. One explanation: Good volition together with the five faculties is called guarding and protecting; because it can protect restraint, it is called restraint, though its essence is not restraint. Another explanation: Because it is guarded and protected by the essence of the precept, it is called guarding and protecting.