John Milton, (1608 - 1674) Sonnet 19 (Sonnet XIX)
When I consider how my light is spent,
Ere half my days, in this dark world and wide,
And that one talent which is death to hide
Lodged with me useless, though my soul more bent
To serve therewith my Maker, and present
My true account, lest He returning chide,
"Doth God exact day-labour, light denied?"
I fondly ask; But patience, to prevent
That murmur, soon replies "God doth not need
Either man's work or his own gifts. Who best
Bear His mild yoke, they serve Him best. His state
Is kingly: thousands at His bidding speed
And post o'er land and ocean without rest;
They also serve who only stand and wait."
Many people refer to this poem as 'When I consider how my life is spent' however when Milton wrote this poem he was referring to his rapidly failing eyesight
William Shakespeare, (1564 1616) Sonnet XV.
When I consider every thing that grows
Holds in perfection but a little moment,
That this huge stage presenteth nought but shows
Whereon the stars in secret influence comment;
When I perceive that men as plants increase,
Cheered and cheque'd even by the self-same sky,
Vaunt in their youthful sap, at height decrease,
And wear their brave state out of memory;
Then the conceit of this inconstant stay
Sets you most rich in youth before my sight,
Where wasteful Time debateth with Decay,
To change your day of youth to sullied night;
And all in war with Time for love of you,
As he takes from you, I engraft you new.
http://www.shakespeare-online.com/sonnets/15detail.html (with paraphrase)