What is a specific event or quote from Act 1 and the effect of foreshadowing ?

Early on in act one, the conversation between Reverend Parris and his niece, Abigail Williams, reveals that she was dismissed from her employment with the Proctors over half a year ago and that no one has attempted to hire her again since then. He says, "it has troubled me that you are now seven month out of their house, and in all this time no other family has ever called for your service." He is concerned about what Abigail might have done to cause the loss of her position, and he is also concerned that it might have tarnished her reputation in the town.
Further, there are rumors in town that Elizabeth Proctor does not often come to Sunday services because "she will not sit so close to something soiled." Parris's concern, as well as the rumors which seem to circulate regarding Abigail's tarnished virtue, foreshadow the revelation that she has, indeed, had an affair with John Proctor. We later learn that this was the reason Elizabeth Proctor fired her, and the rumors about Abigail's lack of sexual innocence do contain some germ of truth in them.

Throughout Act One, Miller reveals the palpable tension in the community of Salem when the Putnams voice their opinions and John Proctor speaks to Abigail. The audience learns that the Putnams deeply resent Reverend Parris's position, as well as Rebecca Nurse's prosperity. The Putnam's negative feelings towards Reverend Parris and Rebecca Nurse foreshadow their involvement and accusations during the witch trials. Another moment that foreshadows a significant future event takes place when John Proctor has a conversation with Abigail. Abigail Williams expresses her feelings for John, as well as her displeasure towards his sick wife, Elizabeth. Abigail tells John,

"Oh, I marvel how such a strong man may let such a sickly wife be—...She is blackening my name in the village! She is telling lies about me! She is a cold, sniveling woman, and you bend to her! Let her turn you like a—" (Miller, 33).

Abigail's hateful comments towards Elizabeth Proctor foreshadow her accusation. In an attempt to get rid of Elizabeth, Abigail accuses her of witchcraft. Ironically, it is John Proctor who is punished because of Abigail's false accusation.