You are reading a tafsir for the group of verses 6:61 to 6:62

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.)