19. This is a sarcastic remark. Its purpose is to bring home to them that the misdeeds about which they are so jubilant, and which they regard as their proud achievements, will ultimately lead them to a painful end.
20. They have spent their efforts and energies in a manner leading to catastrophic results in this world and the Next.
21. No power can make these misdeeds either bear good fruit or prevent them bearing evil fruit. The powers upon which the wrong-doers rely for support in this world and in the World to Come will not be of any help to them.
22. They are asked to acknowledge the Book of God as the final arbiter in all matters, and to submit to its judgement, accepting as right whatever this Book holds to be right, and as wrong whatever it holds to be wrong. The Book of God referred to here is the Torah and the Injil, while the expression 'those who have been given a portion of the Book' refers to the Jewish and Christian religious scholars. (For the Quranic view of the Torah and the Injil see n. 2 above - Ed.)
23. These people considered themselves to be God's favourites and cherished the illusion that, regardless of what they did, they were bound to enter Paradise. They took the view that since they were believers, were descended from pious people, followed noble Prophets, and were disciples and admirers of holy men, Hell would not dare touch them. They also thought that even if they were thrown into Hell they would remain there for a few days only, to be purged of the impurity of the sins which had afflicted them, and would then be sent straight to Paradise. Such notions had made them so bold that even when they committed the most atrocious crimes and the most mortal of sins, and brazenly deviated from Truth and rectitude, their hearts remained utterly unmoved by the fear of God.