Surah 14. Ibrahim, Ayah 51

Its deserts: i.e., according to what it earned by its own acts, good or evil, in its life of probation.

Swift in calling to account: We can understand this in two significations. (1) Let not the wicked think that because Allah, out of His infinite grace and mercy, grants respite, therefore the retribution will be slow in coming. When the time comes in accordance with Allah's Plan and Wisdom, the retribution will come so swiftly that the ungodly will be surprised and they will wish they could get more respite (xiv. 44). (2) On the great Day of Reckoning, let it not be supposed that, because there will be millions of souls to be judged, there will be any delay in judgment as in a human tribunal. It will be a new world and beyond the flight of Time. Or if a metaphor from time as we conceive it in this world can be taken, it will all be as it were in the twinkling of an eye (xvi. 77).