The answer by logic is simple 'Umar had a disagreement with another sahabi about the qur'an whom would he use as an arbiter?
Of course only and certainly our prophet () because the qur'an was revealed to him and he should know best how it was revealed. None except the prophet () can give such a statement or answer as none except him knows about the seven "ahruf"!
Above all of this the context of the dialog is simply to follow:
- The prophet told 'Umar to release the other sahabi (this might not have been mentioned in some variations of the hadith)
- then he (the prophet) asked the sahabi to recite
- and confirmed the correctness of the recitation (while 'Umar confirmed that the sahabi recited as he had heard him recite before)
- then he (the prophet) asked 'Umar to recite and
- confirmed his recitation too.
- And answered the unasked question: "The qur'an was revealed in 7 ahruf"
To help you understand let's check the occurrences of this hadith in hadith compilations:
The hadith you refer to is quoted in Sahih al-Bukhari several times in several chapters:
- In the book of disagreements -Khusoomaat-: (4) Chapter: The talk of opponents against each other -see here- the relevant words mentioned there are:
The Prophet (ﷺ) ordered me to release him and asked Hisham to recite it. When he recited it, Allah s Apostle said, "It was revealed in this way."
He then asked me to recite it.
When I recited it, he said, "It was revealed in this way. The Qur'an has been revealed in seven different ways, so recite it in the way that is easier for you."
The same narration appears in Sahih Muslim here and in al-Muwatta' the source of both al-Bukhari and Muslim. Abu Dawod also quoted it in his Sunan -see here- via a Student of imam Malik and so did an-Nasa-i in his Sunan.
- In the book of Oneness, Uniqueness of Allah (Tawheed): (53)
Chapter: “…So recite as much of the Qur'an as may be easy for you….” -see here- the relevant part there is:
The Prophet (ﷺ) said: "(O 'Umar) release him! Recite, O Hisham."
Hisham recited in the way I heard him reciting. Allah's Messenger (ﷺ) said, "It was revealed like this."
Then Allah's Messenger (ﷺ) said, "Recite, O 'Umar!"
I recited in the way he had taught me, whereupon he said, "It was revealed like this," and added, "The Qur'an has been revealed to be recited in seven different ways, so recite of it whichever is easy for you ."
See also in Sunan an-Nasa-i and Jami' at-Tirmidhi.
- In the book of Virtues of the Qur'an: (5)
Chapter: The Qur'an was revealed to be recited in seven different ways -see here- the relevant part of the hadith there is:
On that Allah's Apostle said, "Release him, (O 'Umar!) Recite, O Hisham!" Then he recited in the same way as I heard him reciting.
Then Allah's Messenger (ﷺ) said, "It was revealed in this way," and added, "Recite, O 'Umar!"
I recited it as he had taught me.
Allah's Messenger (ﷺ) then said, "It was revealed in this way. This Qur'an has been revealed to be recited in seven different ways, so recite of it whichever (way) is easier for you (or read as much of it as may be easy for you).
and in the same book: (27) Chapter: Whoever thinks that there is no harm in saying: Surat Al-Baqarah or Surat so-and-so -see here- with the wording:
The Prophet said, "O Hisham, recite!" So he recited in the same way as I heard him recite it before. On that Allah's Messenger (ﷺ) said, "It was revealed to be recited in this way."
Then Allah's Messenger (ﷺ) said, "Recite, O 'Umar!" So I recited it as he had taught me. Allah's Messenger (ﷺ) then said, "It was revealed to be recited in this way."
Allah's Apostle added, "The Qur'an has been revealed to be recited in several different ways, so recite of it that which is easier for you."
- In the book of Apostates: (9) Chapter: Al-Muta’awwalin -see here- where the relevant wording is:
On that Allah's Messenger (ﷺ) said, "O 'Umar, release him! Recite, O Hisham". So Hisham recited before him in the way as I heard him reciting. Allah's Messenger (ﷺ) said, "It has been revealed like this."
Then Allah's Messenger (ﷺ) said, "Recite, O 'Umar" So recited it.
The Prophet (ﷺ) said, "It has been revealed like this." And then he added, "This Qur'an has been revealed to be recited in seven different ways, so recite it whichever way is easier for you."
From the above narrations in a couple of them it is clearly mentioned that the statement you look for was made by the prophet () and therefore this shows what already was mentioned above the statement about the seven "ahruf" or seven "modes"/"ways" was clearly made by the prophet() as only him could know that
As he was informed by Jibreel before:
-
"The Messenger of Allah (ﷺ) met Jibra'il and said: 'O Jibra'il! I have been sent to an illiterate nation among whom are the elderly woman, the old man, the boy and the girl, and the man who cannot read a book at all.' He said: 'O Muhammad! Indeed the Qur'an was revealed in seven modes.'" (Jami' at-Tirmdihi)
-
The Messenger of Allah (ﷺ) was by a pond belonging to Banu Ghifar when Jibril, peace be upon him, came to him and said: "Allah commands you to teach your Ummah the Quran with one way of recitation." He said: "I ask my Lord for protection and forgiveness, my Ummah cannot bear that." Then he came to him a second time and said: "Allah commands you to teach your Ummah the Quran with two ways of recitation." He said: ""I ask my Lord for protection and forgiveness, my Ummah cannot bear that." Then he came to him a third time and said: "Allah commands you to teach your Ummah the Quran with three ways of recitation." He said: "I ask my Lord for protection and forgiveness, my Ummah cannot bear that." Then he came to him a fourth time and said: "Allah commands you to teach your Ummah the Quran with seven ways of recitation, and whichever the way they recite it will be correct." (Sunan an-Nasa-i)
-
"I had no confusion in my mind from that time I embraced Islam, except when I recited a verse and another man recited it differently. I said: 'The Messenger of Allah (ﷺ) taught me this.' And the other man said: 'The Messenger of Allah (ﷺ) taught me too.' So I went to the Prophet (ﷺ) and said: 'O Prophet of Allah, did you not teach me such and such a verse?' He said: 'Yes.' The other man said: 'Did you not teach me such and such a verse?' He said: 'Yes. Jibril and Mika'il, peace be upon them, came to me, and Jibril sat on my right and Mika'il on my left. Jibril, peace be upon him, said: "Recite the Quran with one way of recitation.' Mika'il said: 'Teach him more, teach him more- until there were seven modes of recitation, each of which is good and sound.'" (Sunan an-Nasa-i)
-
The Prophet (ﷺ) said: "Ubayy, I was asked to recite the Qur'an and I was asked: 'In one mode or two modes?' The angel that accompanied me said: 'Say, in two modes', I said: 'In two modes', I was asked again: 'In two or three modes'. The matter reached up to seven modes. He then said: 'Each mode is sufficiently health-giving, whether you utter 'all-hearing and all-knowing' or instead 'all-powerful and all-wise'. This is valid until you finish the verse indicating punishment on mercy and finish the verse indicating mercy on punishment." (Sunan abi-Dawod)
I don' know which source claims that the hadith number is #2287 in Sahih al-Bukhari, as none of the above on sunnah.com even comes close to that number. But I found the first (from the book of disagreements -Khusoomaat-) referred to by this number on islamweb -see here-
