起信論疏筆削記 13.34

13.34

別中，先明染熏者，據理合然也。以先成染法，方反染成淨，未有先淨後成染法。若先說淨，後說染者，便有妄起無窮之過，亦有悟後更迷之失，故先說染也。

In the specific explanation, first clarifying the perfuming of defilement is in accord with principle. For only after defiled dharmas are first established can one reverse defilement to become pure; there has never been being pure first and subsequently becoming defiled dharmas. If purity were explained first and defilement explained afterward, there would be the fault of delusion arising endlessly, as well as the error of becoming deluded again after enlightenment; therefore, defilement is explained first.