Problem
Throughout both speeches, rhetorical questions were used frequently as a rhetorical device. A question without an answer is known as a rhetorical question. The purpose of this is to convey a message or make a point.
In one paragraph of his speech, Henry uses three rhetorical questions together to prove the same point. He states, "And what have we to oppose to them? Shall we try argument? Have we anything new to offer upon the subject? Shall we resort to entreaty, and shall we resort to entreaty and humble supplication? What terms shall we find which have not been already exhausted?" - This set of questions is used by Henry to demonstrate that they have been engaging in negotiations and arguments for the last ten years without any result. The time for talking is over and it is now time for action, which is war.
As you can see in the speech "A House Divided" Lincoln uses the same approach by using the question, "I ask you can be quite sure that it would not have been voted down, in the one case, as it had been in the other?" - Lincoln questioning the integrity of the law makers and what they are saying, when many times before they have lied and been dishonest. In another section of his speech Lincoln uses a set of rhetorical questions saying, "Did we brave all then to falter now? -now- when that same enemy is wavering, dissevered, and belligerent? - Lincoln is sending the message to not let the efforts that have been made in the past to fight slavery be for nothing just because they are beginning to lose hope that they may not win the fight.
As you can see, both speeches do a wonderful job with rhetorical questioning to prove points. However, I feel that Henry gets people more fired up to join him with the aggression he uses by stating there is nothing more left that they can do. This is it. Lincoln is trying to raise spirits by saying this is not a time to give up just because it seems they may not win.