The Two Soldiers and the Robber explained simply

Two Soldiers travelling together were set upon by a Robber. One of them ran away, but the other stood his ground, and laid about him so lustily with his sword that the Robber was fain to fly and leave him in peace. When the coast was clear the timid one ran back, and, flourishing his weapon, cried in a threatening voice, "Where is he? Let me get at him, and I'll soon let him know whom he's got to deal with." But the other replied, "You are a little late, my friend: I only wish you had backed me up just now, even if you had done no more than speak, for I should have been encouraged, believing your words to be true. As it is, calm yourself, and put up your sword: there is no further use for it. You may delude others into thinking you're as brave as a lion: but I know that, at the first sign of danger, you run away like a hare."