A. Community requires responsible cooperation. Citizenship in heaven does not negate earthly citizenship. B. Role of authority. Force is allowed. They are instruments of God's wrath.
Rewards are also necessary.
Civil authority works out God's purposes in society. Out of respect for God's institution. A. Gov't helped the spread of the gospel, so it fits in with theme of salvation. B. Others see chapter as detached. But contact may be in warning about dangers of Jewish revolutionaries.