Here are a couple of mine to kick this off...

We succeed only as we identify in life, or in war, or in anything else, a single overriding objective, and make all other considerations bend to that one objective.
- General Dwight David Eisenhower


Why should I fear death? If I am, death is not. If death is, I am not. Why should I fear that which cannot exist when I do?
- Epicurus