This is one of my all time favorite quotes. Reading and repeating these words just fills you with courage and makes you feel like you can do anything that you set your mind to. I love how it describes fear as being a mind-killer because that is so true. Fear destroys someone from the inside out, making us crazy or paranoid as it causes us to envision a false reality, give up, or creates a feeling failure. It really cripples your mind and curbs your imagination.
This quote is from the book Dune, which is an amazing story and one I highly recommend to all to read.