What is the meaning of [Don’t kill the goose that lays the golden eggs]

“Take care not to destroy something valuable, such as a source of steady income, through greed, impatience, or a desire for instant gain.”,Martin H. Manser (2007). The Facts on File Dictionary of Proverbs. Infobase Publishing. p. 62. ISBN 978-0-8160-6673-5. Retrieved on 17 August 2013.