"Assisted by that most disloyal traitor / The Thane of Cawdor, began a dismal conflict" (1.3.60-61).
"This supernatural soliciting / Cannot be ill, cannot be good" (1.3.143-144).
In this scene, it introduces the Witches for the first time and begins to show their tone and the mood they create. The share this quote which explains that bad is good and good is bad. This is also the first motif of the play.
"Stars, hide your fires; / Let not light see my black and deep desires" (1.4.57-58).
Ross is discussing with King Duncan what to do with the current Thane of Cawdor because he has betrayed his leader. This also helps to foreshadow that Macbeth will have both the title of Thane of Galmis and Thane of Cawdor.
"unsex me here / and fill me from the crown to the toe-top full / of direst cruelty" (1.5.48-50).
Macbeth is flustered with the idea of the supernatural (witches) telling prophecies that seem to be true. He believes that they can be good, such as the Thane of Cawdor prophecy, but with it will come a cost. A dark cost.
"Look like th' innocent / flower / but be the serpent under't" (1.5.76-78).
Macbeth is thinking of going through with the plan to kill Duncan for the power and title of King. But, he also is fighting with himself because he doesn't to watch so he has to deal with the guilt that comes with it.
Lady Macbeth wants to have her feminine qualities taken away so there is no conflict of gender. This way she doesn't need a husband and have to rule behind someone else's person.
Lady Macbeth is telling Macbeth that he needs to learn to hide his true emotion. Is makes him look weak and is a disadvantage to obtaining power. With this skill, it is easy to keep authority by seeming good, but in reality he's dangerous.