大乘起信論裂網疏 4.8

4.8

Although the tathatā of natural virtue is neither defiled nor pure, because it is free of defilement, it is provisionally named the pure dharma. Like unperfumed clothing, it is spoken of with reference to the undefiled-indeterminate consciousness: it is originally the entire substance of tathatā, and so is directly called tathatā. 'Because nescience perfumes it, there are defiled marks' means that from the perfumed defiled seeds arise the active manifestations of defiled dharmas, fully possessing the three marks, six marks, and so forth, as explained previously.