Iago says, in Act I:
I hate the Moor;
And it is thought abroad, that 'twixt my sheets
He has done my office: I know not if 't be true;
But I, for mere suspicion in that kind, will do as if for surety.
Male Pride & Jealousy: Iago says he suspects that Othello has "done his office"..."twixt" the "sheet" (he has slept with Emilia). Iago cannot prove this outright, but the suspicion alone warrants his revenge. Iago is also jealous that the Moor not only became general, but Othello passed him over for Lieutenant--not to mention the sexual jealousy of marrying a senator's wife.
Dishonor & Reputation: Iago's reputation has been hurt deeply by Othello. He should have been made second in command. In fact, he should have been made general and married Desdemona! Iago will not let a black Muslim win both status symbols, especially in a white Christian city-state such as Venice.
Passion vs. Reason: This play revolves around two passionate, predominately male vices: revenge and jealousy. This quote is the basis for both. Revenge is a by-produce of jealousy, and Iago will use Othello's greatest weakness (jealousy) to enact revenge upon him and Desdemona.
'Reputation, reputation, reputation..... I have lost the immortal part of myself and what remains is bestial' so says poor Cassio to the wily Iago in the play 'Othello' by William Shakespeare. The words are spoken in Act Two Scene Three as Cassio realises that somehow his name has been besmirched and he has fallen in the eyes of a much-loved boss. Iago, of course, has designed it so and it seems as if his plot to discredit his career rival is working. He was passed over for promotion in favor of Cassio even though he thought himself to be the more skilled as a soldier. He realises that it is Cassio's human qualities which has endeared him to Othello and it the reputation of these that he seeks to undermine, attack and destroy. He pretends to comfort Cassio by telling him reputation doesn't matter.