In Elizabeth George Speare's The Witch of Blackbird Pond, Mercy accepts her disability by doing everything she can to make the best of it, which includes devotedly doing what work she can around the house and being a selfless person.
We first learn of Mercy's devotion to work within the first few days of Kit's arrival at the Woods' home. On the first working day of the week, since Kit doesn't own any working clothes, she is set to work helping Mercy card wool. When Kit is overwhelmed by the amount of wool Mercy must usually card by herself, Mercy expresses pride in her ability to work, saying, "Oh, the others help between times. But of course, there are so many things I can't do" (Ch. 4). Besides carding wool, Mercy earns wages by teaching a dame school in the summer months. She is grateful for any means of contributing to the household.
Mercy's selflessness is especially expressed in her treatment of Kit. For example, when Kit confesses to having felt rejected and insulted when, after her arrival, she overheard Judith complaining about her incompetency and wishing Kit was a boy, Mercy's eyes fill with tears at the thought of Kit having been hurt and explains how difficult things have been for Uncle Matthew and Aunt Rachel due to the deaths of their sons. In addition, John Holbrook falls in love with Mercy due to her selflessness, as he expresses when he says to Kit, "I don't want a wife to wait on me. For Mercy just to be what she is--I could never do enough to make up for it" (Ch. 13).