Read this excerpt from a letter by civil war soldier sullivan ballou:

i have no misgivings about, or lack of confidence in the cause in which i am engaged, and my courage does not halt or falter. i know how strongly american civilization now leans on the triumph of the government and how great a debt we owe to those who went before us through the blood and sufferings of the revolution. and i am willing—perfectly willing—to lay down all my joys in this life, to maintain this government, and to pay that debt.

why is this letter an important primary source document?