This quote, which occurs in the final scene of Act 1, shows the beginnings of Iago's plan to get back at Othello. In reading this soliloquy, we learn that Iago hates Othello not just because Othello promoted Cassio to the position of lieutenant, but also because Iago suspects that Othello has slept with Emilia.
Considering this, who said I hate the Moor?
Iago
Subsequently, question is, who is Cassio's wife? Bianca
Consequently, who said I do perceive here a divided duty?
I do perceive here a divided duty. To you I am bound for life and education. These words, which Desdemona speaks to her father before the Venetian senate, are her first of the play.
Who replaces Cassio's Othello's lieutenant?
One of Brabanzio's kinsmen, Lodovico acts as a messenger from Venice to Cyprus. He arrives in Cyprus in Act IV with letters announcing that Othello has been replaced by Cassio as governor.
