بِسْمِ اللَّهِ الرَّحْمَٰنِ الرَّحِيمِ
إِنَّا نَحْنُ نَزَّلْنَا الذِّكْرَ وَإِنَّا لَهُ لَحَافِظُونَ
Indeed We descended the Dhikr and surely We are its preservers. Surat al-Hijr 15:9
Dhikr is that which is remembered, or a reminder. So dhikr is something one had known at some point but had forgotten and not something new.
وَإِذَا رَأَيْتَ الَّذِينَ يَخُوضُونَ فِي آيَاتِنَا فَأَعْرِضْ عَنْهُمْ حَتَّىٰ يَخُوضُوا فِي حَدِيثٍ غَيْرِهِ ۚ وَإِمَّا يُنسِيَنَّكَ الشَّيْطَانُ فَلَا تَقْعُدْ بَعْدَ الذِّكْرَىٰ مَعَ الْقَوْمِ الظَّالِمِينَ
And when you see those who engage in Our Ayat, then turn away from them until they engage in speech other than it. And if Satan causes you to forget, then after the dhikra, do not sit with a people who are Dhalimin. Surat al-An’am 6:68
What’s evident in all these verses is that, the ayat of the Qur’an surely contain dhikr. But is dhikr restricted to the Qur’an?
وَمَا أَرْسَلْنَا قَبْلَكَ إِلَّا رِجَالًا نُّوحِي إِلَيْهِمْ ۖ فَاسْأَلُوا أَهْلَ الذِّكْرِ إِن كُنتُمْ لَا تَعْلَمُونَ
And nor did we We send before you except men whom We inspired. So ask the People of the Dhikr, if you do not know. Surat al-Anbiya 21:7
وَلَقَدْ آتَيْنَا مُوسَىٰ وَهَارُونَ الْفُرْقَانَ وَضِيَاءً وَذِكْرًا لِّلْمُتَّقِينَ
And We had already given Musa and Harun the Criterion and a shining light and a reminder for the Muttaqin. Surat al-Anbiya 21:48
وَمَا كُنتَ بِجَانِبِ الطُّورِ إِذْ نَادَيْنَا وَلَٰكِن رَّحْمَةً مِّن رَّبِّكَ لِتُنذِرَ قَوْمًا مَّا أَتَاهُم مِّن نَّذِيرٍ مِّن قَبْلِكَ لَعَلَّهُمْ يَتَذَكَّرُونَ
And you were not at the side of Tur, when We called, but as a mercy from your Lord that you warn a people to whom no warner had come to before you, so that they may remember. Surat al-Qasas 28:46
There were those who had the Dhikr before the Qur’an was recited to the people of Arabia. So clearly the Dhikr is not restricted to the Qur’an. However, does this mean that all that had ever descended from Allah, in exact words and phrases, has also been preserved?
مَا نَنسَخْ مِنْ آيَةٍ أَوْ نُنسِهَا نَأْتِ بِخَيْرٍ مِّنْهَا أَوْ مِثْلِهَا ۗ أَلَمْ تَعْلَمْ أَنَّ اللَّهَ عَلَىٰ كُلِّ شَيْءٍ قَدِيرٌ
Whatever We abolish of an ayah or cause to be forgotten we bring better than it or similar to it. Don’t you know, Allah is capable over all things. Surat al-Baqarah 2:106.
وَمَا أَرْسَلْنَا مِن قَبْلِكَ مِن رَّسُولٍ وَلَا نَبِيٍّ إِلَّا إِذَا تَمَنَّىٰ أَلْقَى الشَّيْطَانُ فِي أُمْنِيَّتِهِ فَيَنسَخُ اللَّهُ مَا يُلْقِي الشَّيْطَانُ ثُمَّ يُحْكِمُ اللَّهُ آيَاتِهِ ۗ وَاللَّهُ عَلِيمٌ حَكِيمٌ
And We had not sent before you any messenger or prophet except that when he emitted, Satan threw into it. But Allah abolishes what Satan throws in and makes His Ayat precise. And Allah is Knowing, Wise. Surat al-Haj 22:52
So even though an ayah may have been abolished, forgotten, or misconstrued, the Dhikr still exists in other ayat, and stays preserved.
Regarding the Qur’an, Allah says:
وَلَقَدْ يَسَّرْنَا الْقُرْآنَ لِلذِّكْرِ فَهَلْ مِن مُّدَّكِرٍ
And certainly, We made the Qur’an easy for remembrance. So is there any who will be reminded? Surat al-Qamar 54:17
لَا تُحَرِّكْ بِهِ لِسَانَكَ لِتَعْجَلَ بِهِ
Do not move your tongue with it, to hasten with it. Surat al-Qiyamah 75:16
إِنَّ عَلَيْنَا جَمْعَهُ وَقُرْآنَهُ
Indeed, upon Us is its collection and its recitation. Surat al-Qiyamah 75:17
So Allah has taken it upon Himself to gather the Qur’an and preserve the Dhikr. However, this does not mean that all that has been attributed to Musa by the Israelites or all that has been attributed to Muhammad, was also gathered and preserved by Allah.