Sa'di says

On Decrepitude and Old Age

One day, in the pride of my youth, I had travelled hard, and at night stopped, much fatigued, at the foot of a mountain. An infirm old man, who followed the caravan, said to me, "Arise! This is not a place to slumber in." I replied, "How can I proceed, when I have not the power to stir a foot?" He rejoined, "Hast thou not heard that they have said, 'It is better to walk and rest, than to run and be oppressed?' "

Thou who wouldst reach the halting-place, haste not;
Be patient! and my counsel hear aright:
Two courses may be sped by charger hot;
The mule goes slowly, but goes day and night.