Unthrifty loveliness, why dost thou spend
Upon thy self thy beauty's legacy?
Nature's bequest gives nothing, but doth lend,
And being frank she lends to those are free:
Then, beauteous niggard, why dost thou abuse
The bounteous largess given thee to give?
Profitless usurer, why dost thou use
So great a sum of sums, yet canst not live?
For having traffic with thy self alone,
Thou of thy self thy sweet self dost deceive:
Then how when nature calls thee to be gone,
What acceptable audit canst thou leave?
Thy unused beauty must be tombed with thee,
Which, used, lives th' executor to be.

William Shakespeare

http://www.poemhunter.com/poem/sonnet-iv-unthrifty-loveliness-why-dost-thou-spe/