The opening sentence of the second paragraph primarily serves to

- "the die is cast; i have consented to return if we are not destroyed. thus are my hopes blasted by cowardice and indecision; i come back ignorant and disappointed. it requires more philosophy than i possess to bear this injustice with patience. i have lost my hopes of utility and glory; i have lost my friend."

the rhyme scheme is abab cdcd efef gg.

impartial means: treating all rivals or disputants equally; fair and just.

i would say that impartial is agreeing with something, because impartial means to treat your rivals, arguments, and reasoning equally and fair. so if you rival says something, agreeing on it means you did the impartial.