Quote 1
MACDUFF
Either thou, Macbeth,
Or else my sword, with an unbattered edge,
I sheathe again undeeded. There thou shouldst be;
By this great clatter, one of greatest note
Seems bruited. Let me find him, Fortune,
And more I beg not. (5.6.19-24)
This is how to do ambition right: Macduff wants to avenge his family and his king, but he doesn’t seek power for himself. He doesn't want to rule fortune; he's content to be fortune's tool. Clearly, he's going to be the one to take down the boss.
Quote 2
MACDUFF
Malcolm and Donalbain, the King's two sons,
Are stol'n away and fled, which puts upon them
Suspicion of the deed. (2.4.36-38)
You may look guilty when you run—but you look a lot worse when you're dead. Malcolm and Donalbain are willing to put up with the appearance of guilt if it means that they'll be able to avenge their father in the end.
Quote 3
MACDUFF
O gentle lady,
'Tis not for you to hear what I can speak.
The repetition in a woman's ear
Would murder as it fell. (2.3.96-99)
LOL, Macduff. He's so tied to a notion of female gentleness that he can't believe Lady Macbeth could even hear about murder, much less plot one. See, guys? Sexism hurts everyone.