I approached this earlier in another area of the forums, with some responses on where to look. I still cannot find it. I read it in a book about four yr's ago and it was a quote by Emerson. It has stuck by me to this day, though even with my photographic memory I can remember picking up the book, reading it, but only pieces of the quote stick with me. It is about your past and not to hold it against you, to dive deep into the sea and to come out with newfound knowledge and to let it guide you. It is all so shady it comes to me in twisted memory fragments. Which is weird since many of my favorite books or quotes no matter how long ago I saw them remain as vivid to me today as when I first read the book.
"Finish each day and be done with it. You have done what you could; some blunders and absurdities have crept in; forget them as soon as you can. Tomorrow is a new day; you shall begin it serenely and with too high a spirit to be encumbered with your old nonsense.".