D. Repeating the words "if we" emphasizes the number of values that Henry and the audience have in common.
Explanation:
In the excerpt from Patrick Henry's speech, he makes use of parallel structures to further influence the audience. In fact, he repeats the phrase "If we" three times to highlight the importance of the expressions that follow: "be free," "perserve" and not "to abandon the noble struggle" America has been involved in.