I would note that this question is unclear: it never defines who "they" refers to or gives a year to contextualize the statement in general. Just as a point of reference, consider that while Patrick Henry was most famous for his defense of the Revolution against Britain, he was also an avowed anti-Federalist, who opposed the ratification of the US Constitution. Depending on which political context you are working with, you'd be left with a radically different answer to your question.
In any case, Patrick Henry's is most famous for the "Give me Liberty or Give me Death" speech, dated to March 23, 1775, so I am assuming this is what your question is referring to. In this speech, Henry is speaking against Great Britain (which would be the "they" in question). According to Patrick Henry, Britain has been tyrannical and has been marshaling its military forces to bring about an armed suppression of the colonies. For Henry, the war has already started and, with this mind, he makes here a call for armed resistance against the British.