"He who counts tomorrow in his life-term will not have considered death its due consideration. Verily, how many persons start a day, but do not finish it, and how many persons hope for tomorrow, but do not live to reach it? If you contemplate about the end of life and its unpredictability, you will hate long hopes and the deceiving role they have." 

‘Aun b. Abdullah [Jami’ al-‘Uloom wal-’Hikam, page 465, Safwatu as-Safwah 3:103 & Shar’hu As-Sudur, page 21]