Read it through once

IAGO: I follow him to serve my turn upon him: we cannot all be masters, nor all masters cannot be truly followed. You shall mark many a duteous and knee-crooking knave, that, doting on his own obsequious bondage, wears out his time, much like his master's ass, for subjecthood; and many a duteous and knee-crooking knave, that, doting on his own obsequious bondage, wears out his time, much like his master's ass, for subjecthood; and many a dutiful and knee-crooking knave,/* repetition for dramatic effect */—but I will incontinently break with thee.