In William Shakespeare's play "Macbeth", which character states: "Angels are bright still, though the brightest fell"?

This passage from William Shakespeare's "Macbeth" comes at a point in Act IV, Scene 3 in which Malcolm is trying to determine if Macduff is truly on his side against Macbeth, or if Macduff is an agent of Macbeth. The passage ... "Angels are bright still, though the brightest fell" [angels still look like angels, though the brightest of them (Lucifer) fell from grace].

Within the entire scene (Act 4, Scene3), it is one where Malcolm and Macduff are discussing Macbeth’s treachery and tyranny. In a test of Macduff’s patriotism, Malcolm pretends to confess that he would be a hopelessly corrupt womanizer if allowed to rule Scotland. Macduff despairs, confirming to Malcolm that he is truly loyal to his country.

Ross (Ross who is Macduff's cousin and initially a loyal Scottish noble) will later enter and report that Macbeth has had all of Macduff’s family and servants killed. Macduff begins to grieve (“All my pretty ones?”) and Malcolm urges him to turn his grief to vengeance. The two men plan to raise an army against Macbeth.