What is the overall message of raisin in the sun

Can someone explain this to me clearly plz

Read the passage below and answer the question. somehow, it was hotter then: a black dog suffered on a summer’s day; bony mules hitched to hoover carts flicked flies in the sweltering shade of the live oaks on the square. men’s stiff collars wilted by nine in the morning. in the excerpt above, the phrase "stiff collars wilted by nine in the morning" suggests that despite the heat, men still dressed up the men in the town were vain men's clothing appeared its best on hot days the men were not accustomed to wearing nice clothes

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