In the force we take care of our own. No one else does. And even more importantly, another police scandal would do so much harm just as we have a chief commissioner who's beginning to give the public back some faith in law and order. You have to see the bigger picture. And sometimes cruelty is on the side of the good, Macbeth.
-- Banquo (chapter 4)

Importance: Banquo consoles Macbeth with these words when Macbeth confides that he and Duff had in fact illegally killed the second Norse Rider in the final moments of their chase. This quote introduces one of the primary themes of the novel, which is the ethical question of committing bad deeds for a supposedly "good" cause. Shortly after this moment, Macbeth will use a similar strain of logic to induce Banquo to assassinate Malcolm. And, in a tragically ironic moment, Macbeth will use this exact same argument to come...