大方廣佛華嚴經隨疏演義鈔 63.52

63.52

疏「名深淨心」者，此句向上成二平等，以約如法而論等故，名之為深；以約淨法而論等故，名之為淨，故云深淨心也。二者向下，則成此地觀解之心。則五字分二平等，二字是淨所依，其深淨心是能依心。故次引論云「於平等中心得清淨。」言深淨心，即是論經，今經但云「清淨心」耳。

As for the Commentary saying, "is called the deeply purified mind": upward, this phrase completes the two equalities: because equality is discussed in terms of the Dharma as tathatā, it is termed "deep"; because equality is discussed in terms of purified dharmas, it is termed "purified"; hence it is called "deeply purified mind." Second, downward, it completes the mind of contemplative understanding of this stage. Thus these five characters divide into two equalities: the two characters ["deeply purified"] are what the purification relies upon, and the "deeply purified mind" is the mind that relies upon them. Therefore it next cites the treatise saying, "within equality, the mind attains purification." The term "deeply purified mind" comes from the treatise's sūtra text; the present sūtra simply says "purified mind."