成唯識論述記 6.233

6.233

述曰：喻如水精珠能清濁水。濁水喻心等，清珠喻信體，以投珠故濁水便清，以有信故其心遂淨。若爾，慚等例亦應然，體性淨故，斯有何別？

The Commentary states: The simile is that just as a water-clearing jewel can clear turbid water, turbid water is an analogy for the mind and so forth, and the clear jewel is an analogy for the substance of faith; because the jewel is placed [in it], the turbid water then becomes clear, and because faith is present, the mind accordingly becomes pure. If so, shame and the like should by analogy also be like this, since their intrinsic nature is pure; what difference is there then?