“Boldness in battle is nothing out of the way… but to face down fear in cold blood is rare in any man.”

Be bold! That's one way

Source: Medea

Faithless Nellie Gray; reported in Bartlett's Familiar Quotations, 10th ed. (1919).
20th century

Song lyrics, Heaven's Open (1991)

Book IV, line 702 (tr. J. D. Duff).
Pharsalia

Go Rin No Sho (1645)
Context: Third is the Fire book. This book is about fighting. The spirit of fire is fierce, whether the fire be small or big; and so it is with battles. The Way of battles is the same for man to man fights and for ten thousand a side battles. You must appreciate that spirit can become big or small. What is big is easy to perceive: what is small is difficult to perceive. In short, it is difficult for large numbers of men to change position, so their movements can be easily predicted. An individual can easily change his mind, so his movements are difficult to predict. You must appreciate this. The essence of this book is that you must train day and night in order to make quick decisions.

Letters and Papers from Prison (1967; 1997), The Friend
Context: When the spirit touches
man's heart and brow
with thoughts that are lofty, bold, serene,
so that with clear eyes he will face the world
as a free man may;
when the spirit gives birth to action
by which alone we stand or fall;
when from the sane and resolute action
rises the workd that gives a a man's life
content and meaning — then would that many,
lonely and actively working,
know of the spirit that grasps and befriends him...