“These men have resolved to fabricate a shield for their fallacies out of the mantle of pretended religion and the authority of the Bible. These they apply, with little judgment, to the refutation of arguments that they do not understand and have not even listened to.”

Galileo uses both metaphor and hyperbole here. “A shield for their fallacies” is a metaphorical way to describe how Galileo’s detractors use the Bible. This is also hyperbole; fabricating a shield out of a mantle of something is a rather grandiose way to describe what his detractors do.

“They know that it is human nature to take up causes whereby a man may oppress his neighbor, no matter how unjustly, rather than those from which a man may receive some just encouragement.”

Galileo asserts that he knows how human nature works, at least in this particular way, and that all people tend to try to oppress those around them. He does this to explain how his detractors have gained support—it is not because they are right but because people enjoy attacking others.

“I hope to show that I proceed with much greater piety than they do, when I argue not against condemning this book, but against condemning it in the way they suggest—that is, without understanding it, weighing it, or so much as reading it.”

Galileo garners sympathy by making it clear that he has criticisms of Copernicus’s book, even though they may not be the same criticisms his detractors have—or, for that matter, the same criticisms that Duchess Christina has. He still engenders sympathy between himself and his readers, even if they disagree with him.