* Act 1, Scene 2: The Chorus speaks about the "ancient grudge... of civil blood" that has been going on between the two families.
* Act 3, Scene 1: Tybalt speaks about the feud, saying, "What, art thou drawn among these heartless hinds? Turn thee, Benvolio; look upon thy death" This suggests that Tybalt sees the feud as something that is inherent to his nature, and that he is ready to die for it.
* Act 5, Scene 3: The Prince says, "See what scourge is laid upon your hate, That Heaven finds means to kill your joys with love!" This suggests that the feud has been so destructive, that Heaven itself has intervened to try and stop it.