the flame that burns twice as bright burns half as long; the well with sweet water will be the first to run dry
Proverb meaning that brilliant or exceptional things often fade quickly. The literal image is of a well with sweet water being used up first. Used to caution against overexertion or to reflect on fleeting excellence.
The proverb 'the well with sweet water will be the first to run dry' means that the more excellent something is, the sooner it is exhausted.