Late in Act I when Abigail is trying to manipulate the other girls into agreeing with her that all they did was dance in the woods, she tells them "Let either of you breathe a word, or the edge of a word, abou the other things, and I will come to you in the black of some terrible night and I will bring a pointy reckoning that will shudder you." Here she is basically threatening to kill the other girls if they reveal anything about her desire to have Tituba cast a spell to kill Goody Proctor so that she may replace her as John's wife.
Another example is in Act III when Abigail's character has been called into question by Judge Danforth, as a result of the claims of Mary Warren and John Proctor, Abigail even dares to threaten the judge, hoping to manipulate him into believing her rather than Mary and John. She asks him "Let you beware, Mr. Danforth. Think ou be to be so might that the power of Hell may not turn your wits? Beware of it!" She seems to be warning him that she may just accuse him of witch craft.