The arrests of Rebecca Nurse, Martha Corey and Elizabeth Proctor are examples of human cruelty vs. righteousness.
Ann Putnam who has lost seven babies needs to find justice for her loss, she is very self-righteous in seeking the culprit responsible for her grief and shame. She seeks to punish Rebecca Nurse who has many children and grandchildren.
Francis Nurse says: "For murder, she's charged! For the marvelous and supernatural murder of Goody Putnam's babies." Miller (Act II)
Martha Corey is arrested for bewitching Mr. Walcott, because he is unable to keep a pig alive, since she sold him one and it died. Mr. Walcott does not want to take responsibility for the care of the pig, but place blame on Martha Corey. So she is accused of witchcraft.
Giles Corey: "That bloody mongrel Walcott charge her. Y'see, he buy a pig of my wife four or five years ago, and the pig died soon after. So he come dancin in for his money back. So my Martha, she says to him, Walcott, if you haven't the wit to feed a pig properly, you'll not live to own many." Miller (Act II)
At the end of Act II, when Elizabeth Proctor is arrested, Herrick must chain her. This is a travesty, she is not a hardened criminal. But for the sake of righteousness and the court, Elizabeth and the other innocent women must be chained in irons, both hands and feet.