Thus do I ever make my fool my purse,
For I mine own gained knowledge should profane
If I would time expend with such a snipe
But for my sport and profit. (I.iii.)

Iago makes this confession to the audiences immediately after he sends Roderigo off to sell his land. Although he ostensibly convinces Roderigo to amass a small fortune for his own personal advancement, Iago makes it clear here that he intends to manipulate Roderigo in such a way that he will essentially function as Iago’s “purse.” Iago’s confession is the first moment in the play where he indicates the depth of his treachery. No one—even those apparently on his side—will be spared from his plot.

And, good
lieutenant, I think you think I love you. (II.iii.)

Iago speaks to Cassio in these lines. As implied by his use of the phrase “good lieutenant,” the surface meaning of these words has a positive ring. Essentially, Iago tells him, “I think you know I am your friend.” However, Iago’s recursive use of “think” also conceals a deceptive second meaning. To say “I think you think I love you” implies love without actually expressing it. In a single move, then, Iago both comforts Cassio and undermines his trust.

So will I turn her virtue into pitch
And out of her own goodness make the net
That shall enmesh them all. (II.iii.)

Iago utters these lines at the end of a soliloquy in which he further develops his treacherous plot against Othello. Here, he speaks specifically of Desdemona and how he plans to turn her goodness against her. Iago uses two ill-matched metaphors. He initially wants to “turn her virtue into pitch,” which is a sticky, black, tar-like substance. But in mid-sentence Iago shifts from sticky pitch to the image of a web in which he can ensnare all of his enemies. Iago’s treachery runs so deep that he cannot even commit to a single metaphor!