What chiefly struck me was the gentle manners of these people; and I longed to join them, but dared not.

In this quote from Chapter 12, the monster is drawn to the kindness the members of the De Lacey family that he is observing show to each other. Read more about this quote in Quotes by Theme: The Nature of Goodness.

The gentle manners and beauty of the cottagers greatly endeared them to me: when they were unhappy, I felt depressed; when they rejoiced, I sympathized in their joys.

In Chapter 12, the monster recounts his bond with the De Lacey family, who he secretly observes from his hiding place near their cottage. The humans he meets before he stumbles upon the De Laceys are cruel and frightened of him, but as he watches De Lacey, Agatha, and Felix, he discovers that they are kind, gentle, and caring. They inspire empathy in him, one of defining traits of humanity.

I afterwards found that these labours, performed by an invisible hand, greatly astonished them; and once or twice I heard them, on these occasions, utter the words “good spirit” “wonderful.”

In this quote, the monster comments on the fact that before the De Lacey family saw him face to face, they assumed that he was a good person. Read more about this quote in Quotes by Theme: The Nature of Goodness (the second quote for Chapter 12).