There is a fable of an eagle which could outfly another, and the other didn’t like it. The latter saw a sportsman one day, and said to him: “I wish you would bring down that eagle.”

The sportsman replied that he would if he only had some feathers to put into the arrow. So the eagle pulled one out of his wing. he arrow was shot, but didn’t quite reach the rival eagle; it was flying too high. The envious eagle pulled out more feathers, and kept pulling them out until he lost so many that he couldn’t fly, and then the sportsman turned around and killed him.

My friend, if you are jealous, the only man you can hurt is yourself.

Moody’s Anecdotes, pp. 44-45