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The first ayah of chapter 78 of the Qur’an is from where the last juz’ gets its name, Juz Amma. But there’s something unique in the Qur’an here:

عَمَّ يَتَسَاءَلُونَ – 78:1
About what are they asking one another?
Notice the first word is عَمَّ and not the typical عّمَّا that we’re used to seeing, both of which are a conjunction of عن and ما, “about what” or “from what,” etc. Why was the ا omitted?
The reason is the alif (ا) of maa (ما) is dropped when the ما is used for a question and preceded by a harf jarr.
Another example from the next chapter of the Qur’an, 79:

فِيمَ أَنتَ مِن ذِكْرَاهَا – 79:43
In what [position] are you that you should mention it?
Both عن and في are harf jarr and the ما in both of these are used for a question.
More Examples
For those of you interested, here’s two more examples from the Qur’an. Can you spot them?
إِنَّ الَّذِينَ تَوَفَّاهُمُ الْمَلَائِكَةُ ظَالِمِي أَنفُسِهِمْ قَالُوا فِيمَ كُنتُمْ ۖ قَالُوا كُنَّا مُسْتَضْعَفِينَ فِي الْأَرْضِ ۚ قَالُوا أَلَمْ تَكُنْ أَرْضُ اللَّهِ وَاسِعَةً فَتُهَاجِرُوا فِيهَا ۚ فَأُولَٰئِكَ مَأْوَاهُمْ جَهَنَّمُ ۖ وَسَاءَتْ مَصِيرًا – 4:97
فَلْيَنظُرِ الْإِنسَانُ مِمَّ خُلِقَ – 86:5
JazakaAllah khairan for this knowledge. I am studying harf jarr and this is so beneficial.
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