瑜伽論記 5.363

5.363

如是六支，顯示四種尸羅清淨者，初一是受後五是持，望持為本故是所依根本，初句是總，由初受戒名為安住，後五持戒攝之為四名四淨淨，如文所列，此六支義前雖略明，至聲聞地廣說。

Regarding "these six limbs reveal four kinds of purification of morality": the first one is receiving, and the latter five are maintaining; looking to maintaining as the root, it is the fundamental basis. The first phrase is general; through initially receiving the precepts, it is called abiding; the latter five on maintaining precepts subsume them into four, called the four purifications. As listed in the text, although the meaning of these six limbs was briefly clarified earlier, it will be explained in detail when reaching the Śrāvakabhūmi.