I follow to serve my turn upon him:
We cannot all be masters, nor all masters
Cannot be truly follow'd
Bitter about being passed up for Cassio's post, Iago reveals he serves Othello only to serve himself. He points out to Roderigo that men cannot follow leaders if they want to lead themselves. Also, referring to Othello, Iago says that not all men are fit to lead and not all leaders should be followed. This statement is one of the few moments of honesty between Iago and another character. It also is the first seed planted in his game of deception. His suggestion is a subtle mutiny aimed at Roderigo. Iago is enlisting Roderigo in helping him "serve [his] turn" against Othello.
For when my outward action doth demonstrate
The native act and figure of my heart
In compliment extern, ’tis not long after
But I will wear my heart upon my sleeve
For daws to peck at: I am not what I am.
In pursuit of his revenge Iago will become duplicitous, never showing his true emotion to the outside world. The irony of this statement is that he is telling the truth about his dishonesty. Iago knows that if the rest of the characters knew what lurked in his heart, he would be destroyed. Othello and his loyal men would tear him apart, like birds. The idiom "wear my heart on my sleeve" comes from this line in Othello.
And, noble signior,
If virtue no delighted beauty lack,
Your son-in-law is far more fair than black.
Here, black has a dual meaning - referring to Othello's race and also, according to usage of the time, meaning "ugly". At face value, the Duke says that if virtue can be beautiful, then Othello is indeed "fair", or beautiful, as he possesses goodness. However, because Othello is black, this can be interpreted as a backhanded compliment; Othello is more fair (just, gentlemanly) than those of his race. Race is a pervasive theme in the play, as prejudice is pervasive in Venice. Othello is able to rise above the stereotypes, but he is never able to forget what others may feel about him.
I am not merry; but I do beguile
The thing I am, by seeming otherwise.
While speaking to Iago Desdemona says that, though she pretends to be happy, she is really worried about Othello's safety. This passage shows the care she has for her husband, and also that she is capable of hiding her emotion. In this conversation with Desdemona, Iago reveals how little he thinks of women, and that they use their beauty or wit to manipulate men.
Reputation, reputation, reputation! Oh I have lost my reputation! I have lost the immortal part of myself, and what remains is bestial.
After a drunken brawl with Roderigo, Cassio is stripped of his position. Without his rank, he feels like he is nothing. This sentiment is echoed by Othello, who is motivated to kill Desdemona because her affair has besmirched the reputation that he has worked so hard to craft. Both Cassio and Othello believe a man is nothing more than "bestial" without his good name.
Trifles light as air
Are to the jealous confirmations strong
As proofs of holy writ.
In one of Iago's soliloquies, he observes that things that may otherwise seem insignificant are given outsized importance when they confirm an already held belief. In this way Iago, by planting Desdemona's handkerchief, will throw fuel on Othello's already burning jealousy.
O, beware, my lord, of jealousy!
It is the green-eyed monster which doth mock
The meat it feeds on.
Iago warns Othello in order to incite his jealousy, while at the same time seeming to have his best interests at heart. The idiom "green-eyed monster" comes from this line in Othello, and Iago characterizes the emotion as one that consumes the man who revels in it.
It makes us or it mars us.
Having persuaded Roderigo to kill Cassio, Iago makes it clear to him that this act will be chief to their success or lead to their demise.
Yet I’ll not shed her blood;
Nor scar that whiter skin of hers than snow,
And smooth as monumental alabaster.
Yet she must die, else she’ll betray more men.
Put out the light, and then put out the light:
If I quench thee, thou flaming minister,
I can again thy former light restore
Trying to bring himself to kill Desdemona, Othello acknowledges the finality of what he is about to do. However, though he will kill her, he will not mar her beauty in doing so, as Desdemona's beauty/whiteness/light is a symbol of her goodness. Othello believes that murder will maintain her purity, stopping her from betraying others like she has betrayed him.
I have done the state some service, and they know't.
No more of that. I pray you, in your letters,
When you shall these unlucky deeds relate,
Speak of me as I am; nothing extenuate,
Nor set down aught in malice. Then, must you speak
Of one that loved not wisely but too well
Addressing his horrified countrymen, Othello takes responsibility for what he has done and tells them that any good he has done in the past should not pardon him for this foolish act of passion. Othello wants Venice to remember him as honorable in spite of his actions. Like Cassio, Othello believes a man's reputation is "immortal", and he hopes his name will not be sullied by this final chapter of his life.
