After the great rains, the lion was faced with crossing the river that encircled him.  Swimming was not in his nature, but it was either cross or die.  The lion roared and charged the river, almost drowning before he retreated.  Many times he attacked the water, and each time he failed to cross.
 
       Exhausted, the lion lay down.  In his quietness, he heard the river say, "Never fight what isn't here."
 
       Cautiously, the lion looked up and asked, "What isn't here?"
 
       "Your enemy isn't here," answered the river.  "Just as you are a lion, I am merely a river."
 
       Now the lion sat very still and studied the ways of the river.  He watched and listened.  After a while, he walked to where a certain current brushed against the shore.  Stepping in, he floated to the other side.
 
SOURCE: Hugh Prather, The Little Book of Letting Go