As he says in one of his soliloquies, "So will I turn her virtue into pitch, And out of her own goodness make her net That shall enmesh them all" (2.3.327-329). In other words, as Desdemona tries to convince Othello to hire Cassio back by using her godly intentions Iago plans to poison the Moor by insinuating that there is something behind this help. But in any moment of the story Desdemona truly commits a sinful act that could inculpate her. In addition, Iago cynically advises Cassio to go after Desdemona and persuade her to change the Moor's mind. All he wants is that Othello sees them together once, which would directly contribute to his melancholy. His justification for this vicious advice is that "When devils will the blackest sins put on, They do suggest at first with heavenly shows" (2.3.319-320). Aware of his cynical attitude, he suggests to be honorably helping Cassio in his cause. Although Iago clearly recognizes himself as the evil villain in his speeches, he cleverly manages to pose as an honest and trustworthy friend to every character in the story. Sadly, his wickedness last long enough to wreck Othello's mind and cause a tragic end to the story. .
Another important image portrayed in the play is the idea of the Libra scale which Othello lacks to weight in his passion and reason before allowing Iago's seeds of jealousy and hatred to influence his heart. Aware of the Moor's vulnerability, Iago draws his plan and preys on Othello's insecurities. As he says in the end of Act I, "The Moor is of a free and open nature That thinks men honest that but seem to be so; And will as tenderly be led by th' nose An asses are. I have't! It is engend'red! Hell and night Must bring this monstrous birth to the world's light" (1.3.385-390). In other words, Iago recognizes Othello's innocence as a weakness in judging the men around him, and from that begins to set down his plan.