And He is the subjugator over His servants, and He sends over you guardian-angels until, when death comes to one of you, Our messengers [i.e., angels of death] take him, and they do not fail [in their duties].
(It is Allah Who takes away the souls at the time of their death, and those that die not during their sleep. He keeps those (souls) for which He has ordained death and sends the rest for a term appointed.)39:42, ,thus mentioning both minor and major death. Allah says,
In the third verse, this subject has been further enlarged by saying that Allah Ta` ala has absolute subduing power over all His servants. As long as He wills to have them living, He assigns angels to protect them as a result of which no one dares harm them. And when one has reached the appointed limit of one's age, these very guardian angels become the agents of one's death without ever falling short in providing the relevant causes leading to one's death. Then, death is not all, for the matter is still not closed. Instead of that, there is the next phase, that of: رُدُّوا إِلَى اللَّـهِ ; (Then they are returned to Allah - 62). It means that they will be made to rise again and be presented before Allah Ta` ala. If, at this point, one were to think of having to appear before the greatest Judge of judges and stand before Him to account for a whole life-time of deeds, one cannot even dare to imagine to come out unscathed and hope to escape punishment. Therefore, along with it, it was said: إِلَى اللَّـهِ مَوْلَاهُمُ الْحَقِّ to Allah, their real Master - 62). It means that Allah Ta` ala is not only the Sovereign and the Judge of judges, He is also the Master and Guardian of His servants who reaches out to help them at all times of their need.
After that, it was said: أَلَا لَهُ الْحُكْمُ (Beware, to Him alone belongs the judgement). This certainly leaves no doubt that He is the best in His decision and decree. However, one may be inclined to think how it will be possible for Allah who is One alone to take care of the reckoning of age-long deeds of billions and billions of human beings? Therefore, after that, it was said: أَسْرَعُ الْحَاسِبِينَ (and He is the swiftest reckoner). It means that taking what is done by Allah on the analogy of what is done by human beings is ignorance. He shall do that in no time. (When His servants at the Mainframe factories of Cray and IBM can churn billions and billions of data in seconds, why anyone in his senses would ever doubt the power of the Maker of all makers ! -Tr.)
Tazkirul Quran
Maulana Wahiduddin KhanOn ayahs 60–61
God has created this world in such a way that it provides practical examples of those facts to which the attention of human beings is called. If a man does not close his eyes and does not screen off his mind with false veils, he will find in the whole universe practical demonstrations of the Quran’s challenge to man’s thinking processes. Branches emerge from a tree trunk and leaves sprout from the branches, but there is a difference in their respective joints. In other words, the Creator knows that the branches have to remain attached to the trunk, while the leaves have to detach themselves and fall down. If this were not so, the leaves would fail to separate from the branches and the entire system of bringing new life to the tree every year would be upset. Similarly, when a seed is sown, the earth in which it is placed already possesses all the ingredients from which it derives nourishment and finally grows into a full-fledged tree. Then, how is it possible that God who is aware of the conditions of such things as a leaf and a seed could be unaware of the human condition?
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.