She doubted anyone of consequence had seen her stroll here, but there was no reason to take chances with the gossips.”
-- Narrator (chapter 4)

Importance: Mary has gone to the wharf to watch the sailors unloading their ships. Her marriage is a wreck, and she is desperately unhappy and lonely. This shows that Mary is aware that there are people watching and judging, but she fails to take that seriously enough over the coming events.

There were myriad ways to try and keep the Devil at bay, just as there were innumerable ways to invite Him into one's life.”
-- Narrator (5 )

Importance: Mary has just found the two forks buried in her yard and knows this is likely an invitation. This is one example of the role of superstition in the lives of these people.

I know this, ma'am, and this alone: Thou art barren but desire a child. Thou took the Devil's tines and a pestle...
-- Catherine (10 )