These lines are Banquo’s dying words, as he is slaughtered by the murderers Macbeth has hired in Act 3, scene 3. In his dying breaths, Banquo urges his son, Fleance, to flee to safety, and charges him to someday revenge his father’s death. This sets the stage how the play will end, when Macbeth realizes that the Witches’ prophecy will come true, and Banquo’s children will rule Scotland.