One day, in the pride of youth, I had travelled hard and arrived perfectly exhausted in the evening at the foot of an acclivity. A weak old man, who had likewise been following the caravan, came and asked me why I was sleeping, this not being the place for it. I replied: ‘How am I to travel, having lost the use of my feet?’ He said: ‘Hast thou not heard that it is better to walk gently and to halt now and then than to run and to become exhausted?’ 
 
               O thou who desirest to reach the station   
               Take my advice and learn patience.   
               An Arab horse gallops twice in a race.   
               A camel ambles gently night and day.
Saadi Shirazi
http://www.poemhunter.com/poem/ch-06-on-weakness-and-old-age-story-04/