This is an important question when reading The Crucible. Abigail was a trouble-maker. She succeeded in getting the girls to agree to help her lie about Betty. Shortly after that, she made an effort to draw John Proctor out of his finally appropriate relationship with his wife.
Abigail uses the opportunity to accuse several townspeople of being seen "with the Devil" to position circumstances to her advantage. In fact, from the end of Act 1 until the beginning of Act 4, whenever anyone did something that Abigail disagreed with, she got the rest of the girls to help her accuse the person and then she defamed the person and got them killed or at the very least, arrested. In this same manner, she was able to manipulate John Proctor into giving his life away. This phenomenon is most at work with Elizabeth Proctor in Acts 2 and 3 as Abigail sends a poppet home with Mary Warren that Abigail later used to testify that she had been treated as if by voodoo by someone. Then it turns up that Elizabeth has a doll.
Up until this point, Abigail was previously powerless to such adults in the town. She was to be subservient. These accusations brought her new opportunity to exert power over others. The court listened to her and the girls over logical testimony.
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