瑜伽論記 6.307

6.307

不應開紐下，第四解持衣鉢不應開紐等者，謂不應不繫紐。奘法師云：衣下有紐不應開、應繫，不斬不磔，衣不磔裂也。

From 'One should not untie the fastenings' onward, the fourth explains holding the robes and bowl. 'Should not untie the fastenings' and so forth means that one should not leave the fastenings unfastened. Master Xuanzang says: There are fastenings under the robe that should not be untied and should be tied; 'not cut and not torn' means that the robe is not ripped apart.