大般涅槃經義記 5.208

5.208

上來第二廣破計常，「以是義」下總以結之。「無常即苦」破前計樂，「苦則不淨」破前計淨，「我因迦葉先問已答」指上廣顯，如來於前群牛喻中因迦葉問廣明外道畢竟無有常樂我淨，故指顯之。

The above is the second section, which extensively refutes the imputation of permanence. From "By this principle" onward, it concludes it in general. "Impermanence is suffering" refutes the earlier imputation of pleasure. "Suffering is impure" refutes the earlier imputation of purity. "Because Kāśyapa asked earlier, I have already answered" points back to the extensive clarification above: because the Tathāgata, in the earlier parable of the herd of cattle, extensively explained in response to Kāśyapa's question that outsiders ultimately lack permanence, pleasure, self, and purity, he therefore points back to reveal it.