Othello:  Why, how now, ho? from whence ariseth this?
  Are we turned Turks, and to Ourselves do that
  Which heaven hath forbid the ottomites?
  For Christian shame put by this barbarous brawl!
  He hat stirs next to carve for his own rage
  Holds his soul light; he dies upon his motion.
  Silence the dreadful bell, it frights the isle
  From her propriety, What is the matter, masters?
  Honest Iago, that looks dead with grieving
  Speak, Who began this? On thy love, I charge thee

Iago:   I do not know

 (Acts II, Scene Three, Lines 155 - 165) 

The underlined expression refers to the____________