There are twenty such places in the Qur'ân-ul-Majîd where even a little carelessness can make one guilty of the unintentional utterance of words of kufr (disbelief). The changing or transposing of a fat'hah (zabar), kasrah (zayr), or dammah (paysh) can alter the meaning of words, and to intentionally recite incorrectly can plunge one into the act of a major sin (gunâh-e-kabîrah); so much so that it can lead one to the brink of kufr.
There are twenty such places where one should exercise great care; which are listed hereunder.
