What is the purpose of "deluge" stories?

What response does lincoln hope to elicit from his listeners with these words from his gettysburg address "we gave to come dedicate a portion of that field, as a final resting place for those who here gave their lives, that that nation might live. it is altogether fitting and proper that we should do this

Why isn’t the mood saddened by this tragic event

How does hosseini use details of exposition to link amir’s life in afghanistan with his life in the united states?