Elizabeth Proctor and Abigail Williams are two important women in The Crucible. They are basically opposite of each other, which makes their characters vital to the story. Both Elizabeth's and Abigail's roles in the story can be determined by comparing what each women represents, what motivates them, and what they cause in the end.
Elizabeth Proctor represents the only thing good left in John Proctor's life. She is an honest women who would never lie to John, although he has lied to her. While she is suspicious at times, she will never stop loving him. And that is what she has come to represent, love and honesty. While Elizabeth's character is easy to figure out, Abigail Williams is a bit more complex. Abigail is a girl who doesn't have many values. She doesn't uphold anything that would constrict her or keep her from doing what she wants to do at high esteem.
Abby would rather lie her way to innocence than to take responsibility for her actions. So that is what she has come to represent, the secret life of sin in Salem.
Each women has a strong motivation in the story; but there is no telling which is the strongest. Elizabeth's motivation is to keep the peace. So much so that she voluntarily left her home to be taken prisoner. Her rationale behind this was that if she was honest, and her reputation was good for it, then she would become free again. Abigail's motivation is to cause chaos. She would rather tell a lie and be the center of attention than be blamed for something. And her driving force for this was to gain power. Something she had never had before. One thing that they did have in common is that they are both striving to win or keep John's heart. Elizabeth's part in this was to fire Abigail for having an affair with John. Abigail's part in this was to try to kill Elizabeth by blaming her for witchcraft. Both women's reputations were at hand, and they were prepared to fight for it.
Both Abigail and Elizabeth had contributed to John Proctor's death. Abigail with her tails of witchcraft on many women in the town had caused many people's lives to be taken away from them. And Elizabeth's only lie during the story was when she told the judge that John and Abigail had no affair. Her only lie would cause the death of her beloved husband. Both women's relationship with John would be his undoing.
Elizabeth's role as John's darling wife and Abigail's role as the leader of the girls can be determined by comparing what both women represent, what motivates each, and what each one triggers in the end. Both women's characters are fundamentally opposite of each other. Which is why they play key roles in The Crucible.