The Grey Hair
A poem by Yehudah ha-Levi
One day I observed a grey hair in my head;
I plucked it right out, when it thus to me said:
"You may smile, if you wish, at your treatment of me,
But a score of my friends soon will make of you a mockery."
Based on the translation by J. Chotzner that's reproduced on page 428 of A Treasury of Jewish Poetry: From Biblical Times to the Present, edited by Nathan and Marynn Ausubel (Crown Publishers, 1957).