When a man has fulfilled all ...

When a man has fulfilled all four of these requisites-to be wide awake, to have fear, respect, and absolute assurance-there are no mistakes for which he will have to account; under such conditions his actions lose the blundering quality of the acts of a fool. If such a man fails, or suffers a defeat, he will have lost only a battle, and there will be no pitiful regrets over that.
When a man has fulfilled all four of these requisites-to be wide awake, to have fear, respect, and absolute assurance-there are no mistakes for which he will have to account; under such conditions his actions lose the blundering quality of the acts of a fool. If such a man fails, or suffers a defeat, he will have lost only a battle, and there will be no pitiful regrets over that.

Quotes from the same author

The trick is in what one emphasizes. We either make ourselves miserable, or we make ourselves happy. The amount of work is the same.
“We choose whether to be warriors or to be ordinary.”
“A warrior seeks to act rather than talk.”
“A warrior lives by acting, not by thinking about acting, nor by thinking about what he will think he has finished acting.”
“A warrior never worries about his fear.”