What is revealed about Macbeth's character in his first two soliloquies, near the end of Act 1 and the beginning of Act 2?

Macbeth's first two soliloquies, at the end of Act 1 and the beginning of Act 2, are similar in some ways, and different in others. Macbeth tries to decide whether or not to kill Duncan in the first soliloquy, and in the second is responding to a vision of a dagger pointing to Duncan's chamber.

In his first soliloquy, Macbeth cannot decide whether to kill Duncan in the hope of taking his place as king. At first he thinks "If it were done when 'tis done..." hoping that after Duncan was killed, there would be no consequences. However he realises that there would be many consequences. He says "Bloody instructions, which being taught, return / to plague th'inventor", meaning that if teaches the people of Scotland to kill, then they will kill him. He also considers the fact that he is Duncan's "kinsman and his subject... / Who should against his murder shut the door, / Not bear the knife..." He finishes saying he has only "Vaulting ambition which o'erleaps itself / And falls on th'other-".

In his second soliloquy, at the end of Act 2 Scene I, he sees a dagger, hovering in mid air. He reaches out to try to grab it, but "I have thee not, and yet I see thee still." The dagger points towards Duncan's chamber, beckoning. Rather that being too scared, he thinks and wonders whether it is "a false creation / Proceeding form the heat-oppressed brain" or some sort of oracular vision. The dagger starts spurting "gouts of blood". The bell rings, and he leaves to kill Duncan.

Macbeth's conscience plays an important role in his decision not to kill Duncan in his first soliloquy. He thinks how innocent and unsuspecting Duncan is, and compared him to a "naked newborn babe". He thinks of how Duncan has honoured him with the title of Thane of Cawdor, and how he is Duncan's host, so he should "against his murder shut the door, / Not bear the knife myself." He decides that, after all, Duncan didn't do anything to him, and is honouring him, so why should he kill him? He realises that the only reason why he wanted to kill Duncan was ambition, which could not outweigh the many reasons why he shouldn't kill Duncan. This is a good show of conscience from Macbeth.

There are many contrasts in both of Macbeth's first two soliloquies. The first contrast in the soliloquies is the contrast between hosts and murderers. Macbeth says that he is Duncan's host, who "should against his murder shut the door". Then, in the second soliloquy, there is a contrast between sight and touch. He sees the dagger in front of him, but cannot clutch it. This is also the contrast between deception and honesty; his sight deceiving him, and his touch was reliable, similar to Macbeth, who is deceiving, and Duncan, who is trustworthy. The final contrast is the contrast between heaven and hell, in the last line of his second soliloquy. After the bell rings, he says "Hear it not, Duncan, for it is a knell / That summons thee to heaven or to hell."

Both soliloquies use a lot of imagery, but the first one uses much more than the second. The first metaphor Macbeth uses is one describing the vast expanse of time. He says "...here, upon this bank and shoal of time..." referring to this moment of time as only a tiny island in the ocean of time. Then he says "This even even-handed justice / Commends th'ingredience of our poisoned chalice / To our own lips." He describes how killing the king would encourage others also to kill the king, which would be Macbeth himself. Later he compares the innocent, unsuspecting Duncan, to a "naked newborn babe ... or heaven's cherubin". The main piece of imagery in the second soliloquy is the dagger, pointing towards Duncan's chamber. He sees it "in a form as palpable / As this which now I draw". It starts spurting blood, symbolising the blood of Duncan.

In these two soliloquies, a lot is revealed about Macbeth's character. The way he thinks about why and why not he should kill Duncan, and his overall decision not to murder Duncan in the first soliloquy shows that he is not simply a vicious cold-blooded killer, but that he is actually a tragic hero.