Shakespeare's Sonnet 63

Against my love shall be as I am now,With Time’s injurious hand crush’d and o’erworn;When hours have drain’d his blood and fill’d his browWith lines and wrinkles; when his youthful mornHath travell’d on to age’s steepy night;And all those beauties whereof now he’s kingAre vanishing, or vanished out of sight,Stealing away the treasure of his spring;For such a time do I now fortifyAgainst confounding age’s cruel knife,That he shall never cut from memoryMy sweet love’s beauty, though my lover’s life:His beauty shall in these black lines be seen,And they shall live, and he in them still green.

I prepare for when my love is as I am now, crushed and worn out by Time’s cruel hand. The hours will drain his blood and fill his forehead with lines and wrinkles. His young morning will pass into the steep darkness of old age. All the beauties he now rules over will fade or disappear. They will steal away the riches of his youth.
For that time, I now build a defense against old age’s cruel, destructive knife. It may take my lover’s life, but it will never cut his beauty from memory.
His beauty will be seen in these lines of black ink. They will live on, and he will stay young in them.