Mormon lived to see his people turn wholesale away from God. He saw tens of thousands and more slaughtered. And we can see his sorrow as he writes an elegy to his people:

“19 And wo is me because of their wickedness; for my heart has been filled with sorrow because of their wickedness, all my days; nevertheless, I know that I shall be lifted up at the last day.”
It is remarkable therefore that despite the trials he faced, and the sorrow he witnessed, Mormon still retained a bright hope of good things to come. Reading his words reminded me of something I read recently by President Spencer W. Kimball from the October 1974 conference 

“And when we are asked why we are such a happy people, our answer is: “’Because we have everything–life with all its opportunities, death without fear, eternal life with endless growth and development.’”
Even if life does not provide many opportunities for joy, we have the promise of death without fear and of endless opportunities for joy to come. That brightness of hope allowed Mormon to remain faithful and strong even though the world seemed to fall apart.