You can never know everything, and part of what you know is always wrong. Perhaps even the most important part. A portion of wisdom lies in knowing that. A portion of courage lies in going on anyway.
Your body is only clothing. Your flesh will wither, but you are your heart and mind, and they do not change except to grow stronger.
Great captains earned their reputation not just for laying brilliant plans, but for still being able to find victory after those plans began to fall apart.