Henry David Thoreau, 1817-1862
was an US Transcendentalist author
Do what nobody else can do for you. Omit to do anything else.
Helen (Adams) Keller, 1880-1968
was an US blind and deaf educator
I am only one, still I am one. I can not do everything, still I can do something. I will not refuse to do the something I can do.
John Ruskin, 1819-1900
was an English critic, essayist, and reformer
What we think, or what we know, or what we believe is, in the end, of little consequence. The only consequence is what we do.