a mongolian wisdom

A elderly man and boy were drinking tea.
Elderly man : Hey boy, what would happen if I let this Thermos approach to the candle. Boy couldn't answer precisely.
Elderly man wistfully said : The more the Thermos approaches to the candle, the bigger the shadow behind it gets. Just like this, the more you achieve success, the more you are followed by jealousy.
Then elderly man asked again how this shadow would disappear? the boy couldn't answer precisely.
Elderly man : if your spirit, thought and mind are as crystal as glass, this shadow will disappear.