大乘起信論義疏 1.60

1.60

自下第三結前也。「故說為空」者，正結前說，次下釋結。何故空者？「若離妄心實無可空」，真法湛然故。而將妄心所造之物，不得湛故，故說為空也。

From here below, the third [part] concludes the preceding. "Therefore it is spoken of as empty" directly concludes the preceding explanation, and the explanation of the conclusion follows below. Why is it empty? "If free from the deluded mind, there is truly nothing to be emptied", because real phenomena are serene. Yet taking the things produced by the deluded mind, they cannot attain serenity; therefore it is spoken of as empty.