Tafsir

Commentaryمَا أَصَابَ مِن مُّصِيبَةٍ إِلَّا بِإِذْنِ اللَّـهِ ۗ وَمَن يُؤْمِن بِاللَّـهِ يَهْدِ قَلْبَهُ (And no calamity befalls [ one ], but with the leave of Allah. And whoever believes in Allah, He guides his heart…64:11) In other words, it is a reality that not even a particle can move without the Divine will. Without the will of Allah no one can harm or benefit anyone. If a person does not believe in Allah and the Divine destination, he would not have any means of comforting himself when a calamity befalls him. He receives it with despair, and gropes for means of alleviating it. A believer, on the other hand, who reposes his faith in Divine will and destination is guided by Allah, and his heart is filled with peace and tranquility. Allah will guide his heart to certainty that whatever difficulty afflicts him could never have missed him, and whatever adversity has missed him could never have afflicted him. As a result of this belief, he is promised a reward in the Hereafter, which he keeps in view all the time.

This strong belief in the promise of a reward in the Hereafter alleviates the worst calamity of this world.