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قالَ رَسُولُ اللّهِ (صَلَّى اللّهُ عَلَيْهِ وَ آلِهِ وَسَلَّمَ): إِقْرَؤُوا الْقُرآنَ ما ائْتَلَفَتْ عَلَيْهِ قُلُوبُكُمْ وَ لانَتْ عَلَيْهِ جُلُودُكُمْ فَإِذا اخْتَلَفْـتُمْ فَلَسْـتُمْ تَقْرَؤُونَهُ.

The Messenger of Allah (blessings of Allah be upon him and his family) has said: “Recite the Qur’an in such a way that your hearts develop a love for it and your skin becomes softened by it.  However as soon as your hearts become indifferent to it (meaning that the Qur’an has no effect on you), then stop reciting it.”

Mustadrakul Wasa’il, Volume 4, Page 239

قالَ الإِمامُ جَعْفَرُ ابْنُ مُحَمَّدٍ الصّادِقُ (عَلَيْهِ السَّلامُ): مَنْ قَرَأَ الْقُرآنَ كَثِيراً وَ تَعاهَدَهُ بِمَشَقَّةٍ مِنْ شِدَّةِ حِفْظِهِ أَعْطاهُ اللّهُ أَجْرَ هذَا مَرَّتَينِ.

Imam Ja’far ibne Muhammad as-Sadiq (peace be upon him) has said:  “Allah will reward the person who recites the Qur’an a great deal and makes a promise with it to try and memorize it even though it may entail great difficulty, a double reward.”

Thawabul A’mal Page 227

قالَ رَسُولُ اللّهِ (صَلَّى اللّهُ عَلَيْهِ وَ آلِهِ وَسَلَّمَ): فَإِذا أَلْتَبَسَتْ عَلَيْكُمُ الْفِتَنُ كَقَطْعِ الْلَّيْلِ الْمُظْلِمَ فَعَلَيْكُمْ بِالْقُرآنِ فَإِنَّهُ شافِع مُشَفَّع وَ ماحَلّ مُصَدِّق وَ مَنْ جَعَلَهُ أَمامَهُ قادَهُ إِلـى الْجَنَّةِ وَ مَنْ جَعَلَهُ خَلْفَهُ ساقَهُ إِلـى النّارِ.

The Messenger of Allah (blessings of Allah be upon him and his family) has said: “Whenever the waves of calamities encompass you like the dark night, seek refuge with the Qur’an - for it is an intercessor whose intercession will be accepted.  One who takes it as a guide, Allah will lead that person into Heaven; and whoever disregards it or goes against it, will be lead into the Hell fire.”

Fadhlul Qur’an, Page 599

قالَ أَمِيرُ الْمُؤْمِنِينَ عَلِيُّ ابْنُ أَبِي طالِبٍ (عَلَيْهِ السَّلامُ):تَعَّلَمُوا الْقُرآنَ فَإِنَّهُ أَحْسَنُ الْحَدِيثِ وَ تَفَقَّهُوا فِيهِ فَإِنَّهُ رَبِيعُ الْقُلُوبِ وَ اسْتَشْفُوا بِنُورِهِ فَإِنَّهُ شِفاءُ الصُّدُورِ وَاحْسِنُوا تِلاوَتَهُ فَإِنَّهُ أَنْفَعُ الْقَصَصِ.

Amirul Mo’minin ‘Ali ibne Abi Talib (peace be upon him) has said: “Learn the Qur’an for it is the best of narrations, and understand it thoroughly for it is the best blossoming of the hearts.  Seek cure with its’ Light for it is the cure of the hearts.  Recite it beautifully for it is the most beneficial of narrations.”

Nahjul Balagha, Sermon 110 (109 in some books)

قالَ أَمِيرُ الْمُؤْمِنِينَ عَلِيُّ ابْنُ أَبِي طالِبٍ (عَلَيْهِ السَّلامُ):تَعَّلَمُوا الْقُرآنَ فَإِنَّهُ أَحْسَنُ الْحَدِيثِ وَ تَفَقَّهُوا فِيهِ فَإِنَّهُ رَبِيعُ الْقُلُوبِ وَ اسْتَشْفُوا بِنُورِهِ فَإِنَّهُ شِفاءُ الصُّدُورِ وَاحْسِنُوا تِلاوَتَهُ فَإِنَّهُ أَنْفَعُ الْقَصَصِ.
 
Amirul Mo’minin ‘Ali ibne Abi Talib (peace be upon him) has said: “Learn the Qur’an for it is the best of narrations, and understand it thoroughly for it is the best blossoming of the hearts.  Seek cure with its’ Light for it is the cure of the hearts.  Recite it beautifully for it is the most beneficial of narrations.”
 
Nahjul Balagha, Sermon 110 (109 in some books)

قالَ رَسُولُ اللّهِ (صَلَّى اللّهُ عَلَيْهِ وَ آلِهِ وَسَلَّمَ): إِنَّ هذَا الْقُرآنَ هُوَ حَبْلُ اللّهِ وَ هُوَ النُّورُ الْمُبِينُ وَ الشِّفاءُ النّافِعُ فَاقْرَوُؤهُ فَإِنَّ اللّهَ عَزَّوَّجَلَّ يُؤْجِرُكُمْ عَلى تِلاوَتِهِ لِكُلِّ حَرْفٍ عَشْرَ حَسَناتٍ.

The Messenger of Allah (blessings of Allah be upon him and his family) has said: “Surely this Qur’an is the rope of Allah, and a manifest Light (nur), and a beneficial cure.  Therefore, busy yourselves with the recitation of it, for Allah - The Mighty and Glorious – grants the reward of ten good deeds to you for every letter which is recited.”

Biharul Anwar, Volume 92, Page 19

قالَ رَسُولُ اللّهِ (صَلَّى اللّهُ عَلَيْهِ وَ آلِهِ وَسَلَّمَ): نَوِّرُوا بُيُوتَكُمْ بِتِلاوَةِالْقُرآنِ وَ لا تَتَّخِذُوها قُبُوراً كَما فَعَلَتِ الْيَهُودُ وَ النَّصارى.

The Messenger of Allah (blessings of Allah be upon him and his family) has said: “Brighten up your houses through the recitation of the Qur’an, and do not make them (your homes) like graves, similar to what the Jews and Christians have done (by not performing the prayers and worship of God in their house and limiting this to the Synagogues and Churches).”Usulul Kafi, Volume 2, Page 610

قالَ رَسُولُ اللّهِ (صَلَّى اللّهُ عَلَيْهِ وَ آلِهِ وَسَلَّمَ): نَوِّرُوا بُيُوتَكُمْ بِتِلاوَةِ الْقُرآنِ وَ لا تَتَّخِذُوها قُبُوراً كَما فَعَلَتِ الْيَهُودُ وَ النَّصارى.
 
The Messenger of Allah (blessings of Allah be upon him and his family) has said: “Brighten up your houses through the recitation of the Qur’an, and do not make them (your homes) like graves, similar to what the Jews and Christians have done (by not performing the prayers and worship of God in their house and limiting this to the Synagogues and Churches).”Usulul Kafi, Volume 2, Page 610

Assalam-o-alaikum

The overarching importance of the noble Quran, which Muslims believe is the word of God (Allah in Arabic), is underscored in Islam owing to a number of factors such as the following:

1. The Quran is, according to Islam, the last of the revealed scriptures of God. It clearly teaches that all the previous scriptures have been revealed by God Almighty to His prophets, though they were not preserved intact over time. Only the noble Quran has been protected from addition, deletion, or interpolation. That is why Muslims believe that today, only the noble Quran is authentic as the word of God.

And what is more, it is kept intact on a tablet preserved in Heaven for all times. And in fact, the essential message of all the earlier scriptures was extracted from the same tablet, called in the Quran the "Preserved Tablet":
*{Nay, this is a Glorious Quran (inscribed) in a Tablet Preserved!}* (Al-Buruj 85:21-22)

2. God Almighty in the noble Quran clearly states that all the previous scriptures were revealed provisionally for the benefit of a particular people of a particular period. But the noble Quran is the final testament of God revealed for the whole of humanity, until the Day of Judgment. For this reason, all the teachings contained in the former scriptures which were meant to be of lasting value and importance are included in the Quran.

3. Prophet Muhammad (peace be upon him and his family) was the final messenger from Allah to mankind; and he brought the final revelation from God to man. Therefore, the scripture containing this revelation is the last of the sacred scriptures.

The basic message of the noble Quran is the same as the basic message of the previous revelations and books; and the teachings and instructions by which it provides guidance for man are of a universal nature. They apply for all times to come and to all situations.

This revelation corresponds to a critical juncture that marks a stage of cultural, intellectual, and spiritual development in human history.  

4. If you make a careful study of the language and subject of the Quran and the language and subject of other scriptures, you can see the clear difference of the Quran.

As for the Quran, it is the original Arabic Quran that is always called the Quran, not any translation. That is to say, the noble Quran is the only scripture that exists in the same language and form in which it was originally revealed by Allah Almighty to humankind.

5. Another important point to note about the Quran is the perfect harmony between its content and language. We may get to know the meaning of the Quran from a translation, preferably with sufficient explanations. But the beauty of the Quranic language is to a great extent lost to any one who does not know Arabic.

As a matter of fact, the verses of the Quran appeal to our heart and head at the same time; as we see in them a harmony of rhyme, rhythm and reason, a matching of powerful ideas with moving expression.

We should remember that the Quran came at a time in Arabia when poetry was reigning supreme; but the master-poets of the day could not equal the Quranic richness in diction, style, and beauty. Indeed, its haunting rhythms rocked the whole of Arabia from Sudan to Syria and from Morocco to Oman, and continues to awe those who listen to it, even if they do not understand Arabic.

It is noteworthy that while the Quran continues to occupy the pedestal as an abiding model for literary Arabic, the languages of other scriptures have, more or less, become dead languages.

6. In fact, there is no other Book in human history that has molded, and is continuing to mold, the life of generations of people as the Quran. Every verse of the Book has become the unalterable source of a code of laws that govern every aspect of the life of Muslims.

This was a Book that brought into being the renowned universities and centers of learning that awakened a new enlightenment in the world, such as no other civilization of the past could match.

It was indeed a brilliant and lasting miracle of Allah effected through the Quran, which was at the center of a unique spiritual revolution, which shines through history. The Quran helped in forging unity among tribes, races and social classes. It liberated the thought patterns and the ennobled human knowledge.

1.  Its definitionBy linguistic definition: Betterment
Applied definition: Articulating every letter from its articulation point and giving the letter its rights and dues of characteristics.

Rights of the letters are its required characteristics that never leave it.  The dues of the letters are its presented characteristics that are present in it some of the time, and not present at other times.  i.e. the medd, idgham 

2.  Its formation
The words of the Glorious Qur'an and some said Honorable Hadiths also.

3. Its fruits
It is preserving the tongue from mistakes in pronunciation of the Glorious Qur'an during reading.

4.  Its precedence
It is one of the most honored of sciences and one of the best of them due to its relation to Allah’s words.

5.  Its place within the sciences
It is one of the Islamic Law sciences that are related to the Glorious Qur'an.

6.  Its founder
The rule setter from the practical point of view is the Messenger of Allah  because the Qur'an was revealed to him from Allah, the most High, with tajweed, and he, was instructed on it from the Trustworthy, Jibreel, peace be upon him, and taught it to his companions, who then taught it to their followers and so on until it came to us by these chains.  The rule setter from the scientific point of view  is Imam Ali (a.s.) the nearer and most trusted of Prophet(peace be upon him and his family).

7.  Its precept
Knowledge of tajweed is fardh kifayaah, meaning some of the Muslim community must know it, and its application is fardh ‘ain, required by all Muslims (men and women) who have the complete Qur'an or part of it memorized, even if only one surah.

8.  Reasons for its rules
Guarding the Glorious Qur'an and preserving it from distortion.  The Arabs mixed with non-Arabs after the spread of Islam, and the Muslims feared that the Arab tongue would become corrupted with this intermixing.  It then became mandatory for rules to be put down that would preserve the recitation of the Qur'an from mistakes, and guarantee the reader of the Qur'an integrity of pronunciation.

9.  Its principles
The knowledge of tajweed is contingent on four matters:

1. Knowledge of the articulation points of the letters
2. Knowledge of the characteristics of the letters 
3. Knowledge of what rules change in the letters due to the order of letters
4. Exercising the tongue and a lot of repetition.