Iago refers to jealousy as the "green-eyed monster." As this metaphor suggests, jealousy is closely associated with the theme of appearance and reality. For instance, at one point Othello demands that Iago provide "ocular proof" of Desdemona's infidelity—he demands to see reality. But Iago instead provides the circumstantial evidence of the handkerchief, which Othello, consumed by his jealousy, accepts as a substitute for "ocular proof." Othello's jealousy impedes his ability to distinguish between reality and appearance. While the prejudiced characters in the play denigrate Othello as an animal or a beast based on his race, Othello's obvious honor and intelligence makes these attacks obviously ridiculous. Yet when Othello is overcome by jealousy, he does become beast-like, falling into epileptic fits that rob him of the ability to speak intelligibly.
Othello is also not the only character in Othello to feel jealousy. Both Iago and Roderigo act to destroy Othello out of jealousy, with disastrous consequences.
Jealousy Quotes in Othello
For I'll refer me to all things of sense,
If she in chains of magic were not bound,
Whether a maid, so tender, fair, and happy,
So opposite to marriage that she shunned
The wealthy curled darlings of our nation,
Would ever have, t'incur a general mock,
Run from her guardage to the sooty bosom
Of such a thing as thou—to fear, not to delight."
It is the green-eyed monster, which doth mock
The meat it feeds on."
Sees and knows more, much more, than he unfolds."
And have not those soft parts of conversation
That chamberers have, or for I am declined
Into the vale of years – yet that's not much –
If I quench thee, thou flaming minister,
I can again thy former light restore,
Should I repent me; but once put out thy light,
Thou cuning'st pattern of excelling nature,
I know not where is that Promethean heat
That can thy light relume. When I have plucked thy rose,
I cannot give it vital growth again;
It must needs wither."
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;
Of one not easily jealous, but, being wrought,
Perplexed in the extreme; of one whose hand,
Like the base Judean, threw a pearl away
Richer than all his tribe; of one whose subdued eyes
Albeit unused to the melting mood,
Drops tears as fast as the Arabian trees
Their medicinable gum. Set you down this.
And say besides that in Aleppo once,
Where a malignant and a turbaned Turk
Beat a Venetian and traduced the state,
I took by the throat the circumcised dog
And smote him—thus."