I apologize that it's a song lyric, I understand this is a books sub, so delete if you must, but...I have a perfect one from a Simon and Garfunkel song, that hits right in the feels every time I hear it:

"In the clearing stands a boxer and a fighter by his trade, and he carries a reminder of every glove that laid him down or cut him till he cried out...in his anger and his shame, "I am leaving, I am leaving but the fighter still remains.""