In what way does nature, through sunlight, exercise moral judgment in Chapters 16-19 of The Scarlet Letter?

Hawthorne uses nature in general in the same manner as other Romantic authors--it is a moral guide or reminder, a "teacher" of sorts.  Throughout Chapters 16-19, the sunlight generally shows moral approval of characters' actions by appearing and shining directly on them.  Likewise, it withdraws when someone's presence or actions do not meet with its moral guidelines.  Below are several examples:

1. In Chapter 16 as Hester and Pearl walk down the dark, shadowy road,

"The sportive sunlight—feebly sportive, at best . . .withdrew itself"

when the mother and daughter approach.  Little Pearl, also a moral reminder of her mother's sin, notices the sun's retreat and observes that it does not "love" her mother. Pearl follows up by telling her mother that she will run and catch some of the sunlight because it won't run from someone who does not have a letter on her chest.

2.  The most significant example of Hawthorne's juxtaposition of light and darkness appears in Chapter 18.  As Hester and Dimmesdale meet in the dismal forest, they are hidden by the shadows and gray sky.  But when Hester removes her "A" and lets down her hair,

"all at once, as with a sudden smile of heaven, forth burst the sunshine, pouring a very flood into the obscure forest, gladdening each green leaf, transmuting the yellow fallen ones to gold, and gleaming adown the gray trunks of the solemn trees. The objects that had made a shadow hitherto, embodied the brightness now."

Hawthorne continues his symbolism afterward by stating that the sunlight appears because love outshines everything, even the "gloom" of the outside world. Similarly, when Hester pins her letter back on in Chapter 19, the sunlight fades, and Hester is once again covered with "gray shadow."

3.  Finally, in Chapter 19, when Hester and Dimmesdale (still in the forest) find Pearl.  She is standing near the brook "all glorified with a ray of sunshine." The author notes "sympathy" for Pearl, demonstrating that since she was created out of "love" it approves of her existence.