"By Sinel's death I know I am Thane of Glamis" (1.3.71). He is a protagonist of high estate because he is the captain.
"No son of mine succeeding. If't be so far Banquo's issue have I filed my mind By Sinel’s death I know I am Thane of Glamis. But how of Cawdor? The Thane of Cawdor lives A prosperous gentleman, and to be king Stands not within the prospect of belief, No more than to be Cawdor." ( 1. 3. 74-78) He wants to become next King but he kills Banquo.
"For Banquo's issue have I filed my mind; For them the gracious Duncan have I murdered, Put rancors in the vessel of my peace Only for them, and mine eternal jewel Given to the common enemy of man To make them kings, the seeds of Banquo kings." ( 3. 1. 70-75). Macbeth got the murders to help kill Banquo so that his sons won't become king.
"The castle of Macduff I will surprise,Seize upon Fife, give to th’ edge o’ th’ sword His wife, his babes, and all unfortunate souls That trace him in his line. No boasting like a fool; This deed I’ll do before this purpose cool. But no more sights!—Where are these gentlemen?Come bring me where they are." ( 4. 1. 171-177). Macduff hasn't done anything to Macbeth.
"I have done the deed. Didst thou not hear a noise?" ( 2. 2. 19). Macbeth killed the King, he's going to be the King of Scotland.
"It is concluded Banquo, thy soul's flight/ If it find heaven, must find it out to-night" (3.1.140-141). Macbeth's transformation into an evil villain.