On page 115 when Abigail says “Oh Mary, this is a black art to change your shape. No, I cannot, I cannot stop my mouth; it’s God’s work I do what is she symbolizing?

I think this merely represents Abigail's considerable powers of manipulation of the witch court and Mary Warren. Abigail is indirectly threatening Mary Warren by drawing the court's attention towards her and making them believe she to is working for the devil.