Ma yubaddalu alqawlu ladayya wama ana bithallamin lilAAabeed (surah Qaf: 29)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(50:29) My Word is not changed; *36 and never do I inflict the least wrong upon My servants.' *37

Maa yubaddalul qawlu ladaiya wa maaa ana bizal laamil lil`abeed

*36) That is, "It is not My way to change the decisions once taken. The decision that I have taken to east you into Hell cannot be withdrawn, nor can the law that I had announced in the world be changed that the punishment for misleading and for being misled will be awarded in the Hereafter."
*37) The word zallam as used in the original means the one who is highly unjust. It does not mean: "I am unjust to My servants but not highly unjust. " But it means: "If I were unjust to My own servants being their Creator and Sustainer, I would be highly unjust. Therefore, I am not at all unjust to My servants. This punishment that I am giving you is precisely the same punishment which you have made yourselves worthy of. You arc not being punished an iota more than what you actually deserve, for My Court is a Court of impartial justice. Here, no one can receive a punishment which he does not actually deserve, and for which his being worthy has not been proved by certain and undeniable evidence.