Al-e-Imran (The House of Imran) Sura 3: Verse 145
"No soul can die except by Allah's leave according to a prescribed term. If any do desire a reward in this life, We shall give it to him; and if any do desire a reward in the hereafter, We shall give it to him. And swiftly shall We reward those who (serve Us with) gratitude."
In this verse, two weaknesses of the weaker elements in the Muslim community and the hypocrites are pointed out. One, they do not believe that the time of death of every person is fixed and that no one will die before the completion of the prescribed term of life, and that once this term is over, no one will be able to avert death even for a single instant. Therefore, a person's first concern should be to faithfully, firmly and resolutely discharge his obligations towards Allah rather than fleeing from them. The time and manner of every person's death is already fixed and cannot be altered.
The second weakness of the hypocrites was their erroneous belief that whatever they gained or achieved in life was solely due to their own planning and efforts. And they did not want to risk these achievements by being overly concerned with the betterment of their lives in the hereafter. This is because they feared that this could make them lose all their material achievements. This was, however, a totally false and erroneous belief. Allah grants those who worship this world whatever He has decreed for them but they have no share in the reward of the life in the hereafter. As against this, Allah blesses the seekers of the life hereafter with their reward in the life hereafter besides granting them their share of this worldly life as He has decreed for them. Therefore, the correct attitude for a wise person is that he should focus on the life hereafter and be content with whatever Allah grants him of his portion in this world, rather than throw away the eternal blessings of the life in the hereafter and spend all his efforts in vain pursuit of the fleeting pleasures of this transitory life.
"Pondering Over The Qur'an: Surah Ali Imran" - Amin Ahsan Islahi