The Need for Preservation

The Quran is the final revelation sent to mankind to guide us from darkness into light.
ذَٰلِكَ الْكِتَابُ لَا رَيْبَ ۛ فِيهِ ۛ هُدًى لِّلْمُتَّقِينَ
This is the Book about which there is no doubt, a guidance for those conscious of Allah.Quran 2:2
In order for it to be a reliable source of guidance it must be from God and preserved. By Allah’s mercy the Quran is preserved and as such it stands as an eternal source of guidance for those who wish to be guided.
The scriptures of the Jews and Christians are contradictory, and of unknown origin. A person may find some guidance in there, but he will also find much misguidance. A person looking for Truth would not find it, and be on his own to imagine what the Truth should be.
This is where we have philosophers who are full of contradiction and provide no concrete answers to basic questions. If they did, then over the course of thousands of years we should have a book of guidance written by the philosophers. Thus the need for the Quran is abundantly clear.
By Allah’s mercy the Quran has been preserved through text and through memory in its original language. This is significant when we compare it to the New Testament written in Greek, whereas the companions of Prophet ‘Isa Alayhi Salaam spoke Aramaic. How can a person say they have the words of God revealed through His prophet, when it’s not even in the same language?
The Quran being memorized means there isn’t a dependence on the text.
إِنَّا أَنزَلْنَاهُ قُرْآنًا عَرَبِيًّا لَّعَلَّكُمْ تَعْقِلُونَ
Indeed, We have sent it down as an Arabic Qur’an that you might understand.(Quran 12:2)
وَلَقَدْ يَسَّرْنَا الْقُرْآنَ لِلذِّكْرِ فَهَلْ مِن مُّدَّكِرٍ
And We have certainly made the Qur’an easy for remembrance, so is there any who will remember?Quran 54:17
Due to the fact that Muslims recite the Quran throughout their daily prayers, Muslims are constantly thinking and contemplating the words of their Lord. Allah has given man free will, but it is only the Muslim who chooses to return it back to his Lord in full and willing submission.
3 Ways the Quran was Revealed

The preserved Quran was revealed in three ways. It was revealed in a dream, revealed through Angel Jibreel in human form, and in the spiritual form through the ringing of a bell (Philips, 117).
وَمَا كَانَ لِبَشَرٍ أَن يُكَلِّمَهُ اللَّهُ إِلَّا وَحْيًا أَوْ مِن وَرَاءِ حِجَابٍ أَوْ يُرْسِلَ رَسُولًا فَيُوحِيَ بِإِذْنِهِ مَا يَشَاءُ ۚ إِنَّهُ عَلِيٌّ حَكِيمٌ
And it is not for any human being that Allah should speak to him except by revelation or from behind a partition or that He sends a messenger to reveal, by His permission, what He wills. Indeed, He is Most High and Wise.Quran 42:51
The Prophet received a portion of the Quran in a dream. For the prophets their dreams are all true. Suratul Kawthar is the only surah reported to have been revealed in this way.
Anas reported: One day the Messenger of Allah (may peace be upon him) was sitting amongst us that he dozed off. He then raised his head smilingly. We said: What makes you smile. Messenger of Allah? He said: A Sura has just been revealed to me.
Muslim 261 no.790
The Prophet salla Allahu alayhi wa sallam received revlation from Angel Jibreel in the form of direct speech. This form was easier on the Prophet Salla Allahu alayhi wa sallam.
He also received revelation in the form of a reverberating gong. This was the hardest on the Prophet salla Allahu alayhi wa sallam. It would cause him to sweat profusely even on a cold day.
Narrated ‘Aisha: Al-Harith bin Hisham asked Allah’s Apostle “O Allah’s Apostle! How is the Divine Inspiration revealed to you?” Allah’s Apostle replied, “Sometimes it is (revealed) like the ringing of a bell, this form of inspiration is the hardest of all and then this state passes off after I have grasped what is inspired. Sometimes the Angel comes in the form of a man and talks to me and I grasp whatever he says.” ‘Aisha added: Verily I saw the Prophet being inspired Divinely on a very cold day and noticed the sweat dropping from his forehead (as the inspiration was over).
Bukhari pp. 7 no. 2
It is in these three ways that the Quran was revealed over a period of 23 years.
Why Gradual Revelation?

For the People of the Book they questioned why it was revealed in parts, considering previous revelations were revealed completely at one time. Allah responds in the Quran:
وَقَالَ الَّذِينَ كَفَرُوا لَوْلَا نُزِّلَ عَلَيْهِ الْقُرْآنُ جُمْلَةً وَاحِدَةً ۚ كَذَٰلِكَ لِنُثَبِّتَ بِهِ فُؤَادَكَ ۖ وَرَتَّلْنَاهُ تَرْتِيلًا
And those who disbelieve say, “Why was the Qur’an not revealed to him all at once?” Thus [it is] that We may strengthen thereby your heart. And We have spaced it distinctly.Quran 25:32
It Would be Too Much
There are some benefits to the revelation being revealed in a segmented fashion. One is to be gentle with the Prophet. Receiving revelation from Allah was not an easy thing. He would not have been able to bear the entire Quran being revealed all at once.
لَوْ أَنزَلْنَا هَٰذَا الْقُرْآنَ عَلَىٰ جَبَلٍ لَّرَأَيْتَهُ خَاشِعًا مُّتَصَدِّعًا مِّنْ خَشْيَةِ اللَّهِ ۚ وَتِلْكَ الْأَمْثَالُ نَضْرِبُهَا لِلنَّاسِ لَعَلَّهُمْ يَتَفَكَّرُونَ
If We had sent down this Qur’an upon a mountain, you would have seen it humbled and coming apart from fear of Allah. And these examples We present to the people that perhaps they will give thought.Quran 59:21
The Quran Answered Issues as They Came
Another reason for the Quran being revealed gradually, is that the Quran would answer issues Muslims and non-Muslims would have. It helps make the Quran relatable, and easier to understand the context behind the verses.
وَيَسْأَلُونَكَ عَن ذِي الْقَرْنَيْنِ ۖ قُلْ سَأَتْلُو عَلَيْكُم مِّنْهُ ذِكْرًا
And they ask you, [O Muhammad], about Dhul-Qarnayn. Say, “I will recite to you about him a report.”Quran 18:83
As a Proof
A final reason for the gradual nature of the Quran, is a proof that it is not from a man, but from the Creator. The nature of man is that he is ever changing. Due to the experiences of life, man’s perspective, mood, and understanding changes.
Yet the Quran, which is not in the order in which it was revealed has a sense of unity and consistency, that would be impossible for any human to do.
أَفَلَا يَتَدَبَّرُونَ الْقُرْآنَ ۚ وَلَوْ كَانَ مِنْ عِندِ غَيْرِ اللَّهِ لَوَجَدُوا فِيهِ اخْتِلَافًا كَثِيرًا
Then do they not reflect upon the Qur’an? If it had been from [any] other than Allah, they would have found within it much contradiction.Quran 4:82
References
Philips, A.A.B. (1997). Usool At-Tafseer. Dar Al Fatah.
Khan, M.M. (2009). Sahih Bukhari
Sahih International. (1997). Quran (English).
Siddiqui, A. (2009). Sahih Muslim (Vols. 1-43).

A fun moral comic for kids