The cannibals on the island offer Crusoe an opportunity to reflect on the differences between cultures. Should he intervene in their affairs or not? Should he judge their actions, or leave that up to God? He reflects on the topic in the following passage:
Religion joyn'd in with this Prudential, and I was convinc'd now many Ways, that I was perfectly out of my Duty, when I was laying all my bloody Schemes for the Destruction of innocent Creatures, I mean innocent as to me: As to the Crimes they were guilty of towards one another, I had nothing to do with them; they were National, and I ought to leave them to the Justice of God, who is the Governour of Nations, and knows how by National Punishments to make a just Retribution for National Offences; and to bring publick Judgments upon those who offend in a publick Manner, by such Ways as best pleases him. (146)
After much thought, Crusoe realizes that he cannot kill the cannibals, as that would be taking up God's office. It's up to God to punish nations of people who do wrong, not the individual man. Note, however, that Crusoe does later decide to intervene in the cannibals' actions when he sees that they are ready to kill and eat a Spaniard. Why?