What was revealed upon Nabī Sallallāhu ‘Alayhi Wa Sallam was the seven Ahruf. These are basic categories of differences whilst the components contained therein are the variants. For instance, in the category which constitutes the difference of a word being singular or plural, an example is:        (وَالَّذِيْنَ هُمْ لِاَمَانتِهِمْ وَ عَهْدِهِمْ رَاعُوْنَ) ) in the plural form and وَالَّذِيْنَ هُمْ لِاَمَانَتِهِمْ وَ عَهْدِهِمْ رَاعُوْنَ) ) in the singular form. These two words are called variants (Wujuhāt). Similarly, every such difference in the Qur’ān is called a Qirā’at (variant), irrespective of which category of differences it falls under. Therefore, the different Qirā’āt (variants) are components that make up the Ahruf.
Thus, we can conclude that the Ahruf and variants were revealed upon Nabī Sallallāhu ‘Alayhi Wa Sallam. As for the first type of Qirā’āt, they were not exactly revealed as they are recited nowadays. Further explanation on this shall soon be given later on.
Note: At times, the word Qirā’at is used to refer to the subject or science of Qirā’at. This usage will be evident from the context it is used in.
 
Revelation of Qirā’āt (variants)
The revelation of the different Qirā’āt (variants) began after the emigration to Madīnah. When droves of people from different tribes started embracing Islam and they found it difficult to recite the Qur’ān, Allāh eased this difficulty by revealing the different Ahruf and Qirā’āt.
Till Nabī’s Sallallāhu ‘Alayhi Wa Sallam emigration to Madīnah, whatever was revealed could only be recited in one manner. There were no differences or variants in any word.[10]
It should be noted that the different Qirā’āt (variants) are not a variation of narrations but they are a variation of revelation. This means that all the acceptable Qirā’āt (variants) were revealed as they are and the differences are not due to different narrations of the same word.[11]
As for the science of Hadīth, many such narrations of a single Hadīth can be found which differ in their wordings. This is mostly because it was permissible to narrate a Hadīth in one’s own words as long as the meaning was maintained. This caused a variation of narrations. But this was not permissible when narrating the Qur’ān. It was necessary to maintain the original words. Therefore, it is understood that the variants of the Qur’ān were revealed as they are whilst the many variants of the Hadīth are the work of the narrators.[12]
 
Narration of Qirā’āt (variants)
Nabī Sallallāhu ‘Alayhi Wa Sallam taught the Sahābah the Qur’ān as it was revealed. In this way many Sahābah learnt much of it directly from Nabī Sallallāhu ‘Alayhi Wa Sallam. But many of them learnt great portions of it from each other due to Nabī’s Sallallāhu ‘Alayhi Wa Sallam engrossment in other responsibilities of prophet hood. These noble Sahābah took great precaution in narrating and teaching whatever they had learnt. They would not tolerate the slightest of alterations in the Qur’ān.
 The Sahābah’s knowledge with regards to the Qur’ān differed from each other. There were those who had memorized most of the Qur'ān in Nabī’s Sallallāhu ‘Alayhi Wa Sallam era while others had only learnt a portion of it.
After the demise of Nabī Sallallāhu ‘Alayhi Wa Sallam, the wars and conquests of many surrounding countries began. Due to this, the Sahābah dispersed in different directions and taught the new Muslims what they knew of the Qur’ān according to the different Qirā’āt (variants) they had learnt. Thus, the narration of the Qur’ān with its different Qirā’āt (variants) began.
But the protection, propagation and narration of the Qur’ān were much more complicated than it seemed. Together with the many acceptable and reliable variants, people later narrated such variants that were not proven to be part of the Qur’ān. This was because they were unaware that these variants had either been abrogated or had some other discrepancies. These unacceptable variants were of a few types:

As Islām spread quickly, these unacceptable variants quickly spread all over the Muslim empire. A mixture of acceptable and unacceptable variants and narrations mushroomed in all the major cities that were the centres of learning.
But Allāh’s promise of safeguarding the Qur’ān was never to fail. He created such men who dedicated their lives to this cause. They collected, researched and taught the acceptable Qirā’āt (modes) and variants. They separated what truly was the Qur’ān from the rest. The work of these great personalities marked the inception of a new chapter in the history of the science of Qirā’at.
 
Background of The Sab’ah (Seven) Qirā’āt
The differentiation of the reliable Qirā’āt and variants began as early as the first century A.H. And as has always been the system of Islām that its preservation is wholly based on memorisation of knowledge and its transmission from heart to heart, the Qirā’āt and variants too were narrated in this manner. The tradition of compiling and gathering these Qirā’āt in script started much later. Although the earliest book is dated as early as the end of the first century A.H.,[13] most of the famous and authentic books only appeared in the 3^rd century and onwards.
The purpose of these books was to serve only as a secondary means of safeguarding the Qirā’āt and variants. Just as the narration of the Qur’ān was based on memorisation and the compilation of its script was mainly to serve as a backup for its safeguarding in case of the loss of Huffāz or some other calamity, the safeguarding of the Qirā’āt and variants was exactly the same. These books would only serve as a backup or reference.
As for the preservation by heart, many ‘Ulama sifted through the thousands of narrations and filtered them to attain the authentic variants. For this, they searched for the most authentic narrators they could find in their eras and areas and only narrated from them. And preservation of Dīn – especially the Qur’ān – being a great responsibility upon the Ummah, they placed the most stringent of measures to serve as a yardstick in accepting and rejecting Qirā’āt (variants).
The conditions that a Qirā’at (variant) would have to meet in order to be considered part of the Qur’ān were three (3):

Note: From here onwards, wherever the word ‘acceptable’ is used in relation to Qirā’āt (modes) and variants, it will mean that they conform to these 3 conditions. And where the words ‘reliable’ or ‘authentic’ are used will mean that such Qirā’āt (modes) and variants have authentic chains of narration but not as mentioned in the third condition regardless of whether they meet the other 2 conditions or not.
Whichever Qirā’āt (variants) met all three conditions were considered acceptable. These conditions remained the yardstick throughout the centuries and ‘Ulamā’ based their research on these.[16]
Many ‘Ulamā’ singled out the acceptable variants and rejected the rest and these continued to be narrated from heart to heart. But with the overwhelming presence of so many unacceptable and unauthentic variants, many people were still in the dark with regards to the acceptable ones.
The 3^rd century saw the appearance of many compilations of Qirā’āt (modes) and variants. These compilations were of 2 types:

This resulted in different counts of Qirā’āt in each compilation. Some compiled 5, whilst others had 7, 8, 10, 14, and 25. Some had even greater numbers.
From amongst these ‘Ulamā’, the personality of Imām Abū Bakr Ibn Mujāhid[18] Rahimahullāh – who passed away in 324 A.H. – stands out. Many others accomplished this task before and after him but his fame and acceptance in the Muslim empire was so overwhelming that he was considered the highest authority on Qirā’at during his era. Due to this, his book which consisted of the Qirā’āt of seven A’immah gained widespread acceptance and fame all over the Muslim world.
Such great was the fame of Imām Ibn Mujāhid Rahimahullāh that Imām Jazrī Rahimahullāh says, “I have no knowledge of any Imām of Qirā’at whose students were greater in number then those of Ibn Mujāhid. And we have not heard of greater crowds of students around anybody than those around him.”[19]
Therefore, thousands of students studied these Qirā’āt under him and many others learnt them from his students. Thus, a trend of narrating only these seven Qirā’āt began despite the presence of many other acceptable ones some of which were even more accepted by the ‘Ulamā’ then these. Eventually these came to be known as the Sab‘ah (seven) Qirā’āt. These were the Qirā’āt of Imām Nāfi‘ Madanī Rahimahullāh, Imām Ibn Kathīr Makkī Rahimahullāh, Imām Abū ‘Amr Basrī Rahimahullāh, Imām Ibn ‘āmir Shāmī Rahimahullāh, Imām ‘āsim Kūfī Rahimahullāh, Imām Hamzah Kūfī Rahimahullāh and Imām Kisā’ī Kūfī Rahimahullāh.
Imām Ibn Mujāhid Rahimahullāh researched the various prevalent Qirā’āt and variants for years. He did not only suffice at this, but he also analysed and researched the narrations of those narrating from the A’immah. He mastered and taught these seven Qirā’āt for many years, exerting all his time, energies, knowledge and capability. Finally, satisfied with his choice, he compiled them in his famous book called Kitāb-us-Sab‘ah Fil Qirā’āt.[20]     
There is a great misconception amongst the people that the term Sab‘ah (seven) Ahruf in the Hadīth refers to the Sab‘ah Qirā’āt. This claim and concept is totally baseless. The Sab‘ah Qirā’āt are a great portion of the seven Ahruf but not the seven Ahruf themselves. It is mere coincidence that both are seven in number.[21] It is evident that Imām Ibn Mujāhid Rahimahullāh only chose the 7 A’immah out of the many acceptable ones in the 4th century whilst the Sab‘ah Ahruf were revealed in the beginning of the 1st century. How can the Hadīth of Sab‘ah (seven) Ahruf then be referring to something that was only done 3 centuries later!
The choice of these A’immah and their Qirā’āt was largely based on the fact that they were widely accepted in their respective cities. It was as though the people approved of these Qirā’āt. This was due to a few reasons: 

Note: It is important to note that there were other A'immah who also had these characteristics in them but were not included in these seven. The acceptability of their Qirā'āt was no less than these. The compilations of many other ‘Ulamā’ other than Imām Ibn Mujāhid Rahimahullāh included these Qirā’āt.
These seven A’immah had many narrators who preserved and narrated the Qirā’at of their respective Imām. At times, the narrators were direct students of the Imām and at times they narrated through the means of the students of the Imām. Many times, they would differ with each other in certain variants. This was due to their Imām having taught some of them certain such variants which he did not teach the others.
‘Ulamā’ then only chose two narrators for each Imām and left out the rest, thus choosing a total of 14 narrations. The reason for choosing two was the same as that of choosing the seven Qirā’āt i.e. abridging the Qirā’āt for learning and narrating purposes. They carefully chose these particular narrators because their narrations encompassed most of what the other narrators had.[23]
These narrators were those who are known today as Imām Warsh who is a narrator of Imām Nāfi’s Qirā’at, Imam Hafs who is a narrator of Imām ‘Āsim’s Qirā’at, etc.
But Imām Ibn Mujāhid’s Rahimahullāh work gained so much fame that many Muslims were led to believe that these were the only acceptable Qirā’āt and narrations. Anything beyond this was deemed unacceptable whereas this contradicts reality.
 
Background of The ‘Asharah (Ten) Qirā’āt
Despite many people clinging on to the Sab‘ah Qirā’āt, there still were other authentic and acceptable Qirā’āt present. Although they were not as famous as the seven, large numbers of people had accepted them. They were also taught, learnt and narrated. History bears testimony that rather than learning the Sab‘ah Qirā’āt, many people only learnt these Qirā’āt. Therefore, their reliability and acceptability was no less than the Sab‘ah Qirā’āt.
But the acceptability of any Qirā’at largely depends on how many people learn and narrate it in every era. If enough people do not narrate it, then it might still be reliable but not proven to be a part of the Qur’ān if it has any discrepancies from those mentioned previously. So from these other Qirā’āt, 3 continued to be narrated extensively through numerous authentic unbroken chains of narrators, thus meeting the 3 conditions for the acceptance of a Qirā’at that we previously discussed. These were the Qirā’āt of Imām Abū Ja‘far Yazīd Ibn Qa‘qā‘ Rahimahullāh, Imām Ya‘qūb Al-Hadramī Rahimahullāh and Imām Khalaf Ibn Hishām Rahimahullāh.
Imām Khalaf Rahimahullāh, who is a narrator of Imām Hamzah Rahimahullāh of the Sab‘ah Qirā’āt, has his own choice of acceptable variants which are relatively different from his narration from Imām Hamzah Rahimahullāh (in the Sab‘ah Qirā’āt). These variants form a whole separate Qirā’at which is part of these three Qirā’āt.
These three came to be known as the Thalātha (Three) Qirā’āt and these combined with the Sa‘bah (Seven) Qirā’āt came to be known as the ‘Asharah (Ten) Qirā’āt. The term Sa‘bah Qirā’āt was coined in the beginning of the 4^th century by Imām Abū Bakr Ibn Mujāhid Rahimahullāh whilst the term ‘Asharah Qirā’āt was coined in the mid 4^th century. The first personality who compiled these 10 Qirā’āt was Imām Abū Bakr Ibn Mahrān[24] Rahimahullāh – who passed away in 381 A.H.[25] He maintained the system of choosing Qirā’āt adopted by Imām Ibn Mujāhid Rahimahullāh. His work encompassed all the acceptable Qirā’āt present.
Apart from these 10 Qirā’āt, there still were a few others that were famous and reliable to a large extent. But they did not gain much acceptance in their respective cities and were not learnt and narrated by enough people. Some of their variants also did not match the ‘Uthmānī orthography (script). These Qirā’āt have also been compiled by ‘Ulamā’ but for reasons other than the preservation of the Qur’ān. This is because they are not proven to be part of the Qur’ān. There are 4 such Qirā’āt.[26] These make up the Arba‘-‘Asharah (Fourteen) Qirā’āt.
The compilations on Qirā’at after this were mostly based on the Sa‘bah or ‘Asharah Qirā’āt. ‘Ulamā’ either followed in the footsteps of Imām Ibn Mujāhid Rahimahullāh, gathering a few famous Qirā’āt, and expounded on them, or they gathered the ‘Asharah Qirā’āt in trying to gather and expound on all the acceptable Qirā’āt. And because the compilation and narration of Qirā’āt had other benefits apart from safeguarding the Qur’ān, the unreliability of many other Qirā’āt did not stop the ‘Ulamā’ from compiling them and deriving other benefits. Therefore, till now some ‘Ulamā’ have also been compiling the unacceptable Qirā’āt.
The Sa‘bah Qirā’āt remained more popular then the ‘Asharah Qirā’āt throughout the ages. This may have been due to the fact that ‘Ulamā’ wrote such books on the Sa‘bah Qirā’āt which were easy to understand[27] or memorise[28], facilitating easy learning of these Qirā’āt. Such books on the ‘Asharah Qirā’āt were not easily found or were not found at all. Much later, ‘Ulamā such as Imām Jazrī Rahimahullāh – who passed away in 833 A.H. – compiled such books either separately for the Thalāthah Qirā’āt[29] or comprehensive books for the ‘Asharah Qirā’āt.[30]
 
And Allah Ta’āla Knows Best
Nabeel Valli
Student Darul Iftaa
Lusaka, Zambia
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net 
 
Note From Mufti Ebrahim Desai Dāmat Barakātuhu:
Students of Hadīth experience much difficulty in understanding the Hadīth:
أنزل القرآن على سبعة أحرف
Many misunderstand Sab’ah Ahruf as the famous Sab’ah Qirā’āt, Moulānā Nabeel Valli has also studied Qirā’āt and compiled a treatise on the intricacies of the topic. In this brief, Moulānā Nabeel Valli very simply explains the background of Ahruf being the categories/types of differences a Qirā’at and the different recitations of the Qurrā’ will revolve around. While Sab’ah Ahruf itself is a revelation, it is not necessary that the Sab’ah Qirā’āt itself is a revelation. This brief is very useful in understanding some of the intricacies of Qirā’at.