My glass shall not persuade me I am old, <br /> So long as youth and thou are of one date; <br /> But when in thee time's furrows I behold, <br /> Then look I death my days should expiate. <br /> For all that beauty that doth cover thee <br /> Is but the seemly raiment of my heart, <br /> Which in thy breast doth live, as thine in me: <br /> How can I then be elder than thou art? <br /> O, therefore, love, be of thyself so wary <br /> As I, not for myself, but for thee will; <br /> Bearing thy heart, which I will keep so chary <br /> As tender nurse her babe from faring ill. <br /> Presume not on thy heart when mine is slain; <br /> Thou gavest me thine, not to give back again.<br /><br />William Shakespeare<br /><br />http://www.poemhunter.com/poem/sonnet-xxii/
