大般涅槃經疏 19.22

19.22

此是第三明嬰兒行。有師言：借譬得名，權智為體、化物為用。今明涅槃非大小亦得論大小，小即嬰兒行、大即如來行，權智為體可施黃葉，此不得在如來之行。文為三：初明嬰兒、次釋嬰兒意、三結嬰兒果，上聖梵兩行皆爾，此不應無。

This is the third [section], clarifying infant practice. Some masters say: It takes its name borrowed from a parable; provisional wisdom is its essence, and transforming beings is its function. Now it is clarified that although nirvāṇa is neither great nor small, one can also discuss great and small: the small is the infant practice, and the great is the Tathāgata's practice. With provisional wisdom as its essence, one can give yellow leaves [as pretend gold], but this cannot reside within the Tathāgata's practice. The text has three parts: first, clarifying the infant; next, explaining the meaning of the infant; third, concluding with the fruit of the infant. The Noble and Pure practices above were both like this, so this should not be without it.