Having argued at length in favor of monarchial commonwealths as the strongest form of government, Hobbes turns to the relationship between Christianity and civil sovereignty. Of particular concern for the author is the question of how humankind might best serve and obey God while also obeying its sovereign leaders. Although he believes that the word of God as laid down in the Old and New Testaments is infallible, Hobbes grants that humans, learned and otherwise, find great difficulty in interpreting it.

In defining what is scripture and what is not, Hobbes identifies no books aside from those acknowledged by the Church of England, the sect of Christianity that broke off from the Catholic Church in 1534. Although he doesn’t doubt the divine authority of the histories and prophecies found in the Old Testament, along with the gospels and epistles of the New Testament, Hobbes poses a question that is central to Part 3: Do the Christian kings and assemblies who rule as sovereigns in Christian commonwealths hold absolute power over their territories and dominions? Or are they subordinate to a central vicar—specifically the pope—who may judge, depose, or even sentence to death any Christian sovereign he wishes?