The main idea or overall impact you want to form in the minds of your readers is called the

"the sandy walls seemed to collapse in on themselves"

and

"the bloodshot waters seemed to have no bottom"

answer: from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion—that we here highly resolve that these dead shall not have died in vain, that this nation under god shall have a new birth of freedom, and that government of the people

explanation: