Witches tend to be women. In Shakespeare's time, I assume that women were witches since Hecate is a woman who is goddess of witchcraft. I don't believe there's any report of a man being accused of witchcraft and being killed for it.
It is important that witches reappear in Act 4 of MacBeth because they tell him of his future. This helps to shapes many of the events later in the story.
The witches in Macbeth refer to themselves as the "weird sisters."
MacBeth meets the three witches with lady MacBeth
Macbeth.
The witches only gave Macbeth prophecies. It was his decision to do so after Lady Macbeth persuaded him. Although the witches' intentions was probably to cause this murder, the witches did not make Macbeth muder Duncan.
Macbeth did not like what the witches had told him.
The witches don't make Macbeth perform any dark acts, such as killing King Duncan; they just put the idea in his head. The witches tell Macbeth he is the Thane of Cawdor (which he doesn't know yet) and also tell him that he will be king. Once Macbeth finds out he is in fact the Thane of Cawdor, he begins to believe the witches' prophecies. Lady Macbeth convinces him that the only way Macbeth can be king is by killing King Duncan, and he does so. The witches' role in making Macbeth a tragic hero is to serve a catalyst for Macbeth's dark thoughts.
No, the witches are proclaiming and predicting that Macbeth will be king and they are praising Macbeth.
Macbeth does.
Lady Macbeth echoes the words of the witches when she says "All hail, Macbeth, that shalt be king hereafter!". This echoes the witches' prophecy that Macbeth will become king.
Banquo and Macbeth. And the other witches, of course.
I think that Macbeth was at first not as "worried" about the witches and their curses as then on in the play he finds out that every thing that the witches has been tellin him are true.