So I found this quote by Dr. Chalmers in Samuel Smiles book «Character». I think this refers to Thomas Chalmers. Anyway, it led me to a pile of great quotes by John Burroughs:
“The Kingdom of Heaven is not a place, but a state of mind.”
“The secret of happiness is something to do”
“A man can fail many times, but he isn’t a failure until he begins to blame somebody else”
“If you think you can do it, you can”
“Leap, and the net will appear.”
“The lure of the distant and the difficult is deceptive. The great opportunity is where you are”