Ruling on one who, whilst praying, switches between the seven modes of recitation that were narrated via mutawaatir reports

The seven modes of recitation were all narrated from the
Prophet (blessings and peace of Allah be upon him) in mutawaatir reports.
This is something that is well known in Islam, therefore it is permissible
to recite in any one of them. We have explained this matter in detail in
fatwa no. 178120. 

With regard to combining two or more modes of recitation in one prayer or
one rak‘ah or outside the prayer, the scholars differed concerning that and
there are three points of view: 

1.

The first view is that of those who regard it as permissible in all cases,
based on the fact that all of the modes of recitation from Allah, may He be
glorified. Ibn al-‘Arabi said in Ahkaam al-Qur’an (2/613):

Once the modes of recitation are proven and the pronunciation is determined,
no one is obliged to recite only with the mode of recitation of one person,
such as Naafi‘, for example, or ‘Aasim. Rather it is permissible for him to
recite al-Faatihah pronouncing its words according to three different modes
of recitation, because all of it is Qur’an. End quote. 

In Majmoo‘ Fataawa Ibn Taymiyah (22/445) it says: 

He was asked about a man who leads people in prayer and recites according to
the recitation of Shaykh Abu ‘Amr. If he recites according to the recitation
of Warsh or Naafi‘, as they are different recitations, even though he mostly
recites according to the recitation of Abu ‘Amr, will he be sinning or does
that detract from his prayer or will it be rejected? 

He replied: It is permissible to recite part of the Qur’an according to the
recitation of Abu ‘Amr and part according to the recitation of Naafi‘,
whether that is in one rak‘ah or over two rak‘ahs, and whether that is
outside of prayer or in the prayer. End quote. 

2.

The second view is that of those who regarded that as permissible on
condition that what he recites in the second rak‘ah is not connected to what
he recited in the first. An-Nawawi said in al-Majmoo‘ Sharh al-Muhadhdhab
(3/392): If he recites according to one of the seven modes of recitation, it
is mustahabb to complete the recitation in the same mode. But if he recites
some of the verses in one mode and some in another of the seven modes, it is
permissible, on condition that what he recites in the second rak‘ah is not
connected to what he recited in the first. End quote. 

Ibn al-Jazari said in an-Nashr fi’l-Qiraa’aat al-‘Ashr (1/18): 

Al-Habr al-‘Allaamah Abu Zakariyya an-Nawawi said in his book at-Tibyaan:
If the reciter begins in one of the seven modes of recitation, he should
continue with that mode so long as the words are connected. If the section
ends, then he may recite with another of the seven modes of recitation, but
it is better to carry on in the same mode of recitation in that session. End
quote. 

To see this topic in the books of the Shaafa‘is, please see
Asna’l-Mataalib fi Sharh Rawd at-Taalib (1/63); al-Iqnaa‘ fi Hill
Alfaaz Abi Shujaa‘ (1/105); Mughni al-Muhtaaj ila Ma‘rifat Ma‘aani
Alfaaz al-Minhaaj (1/153). 

Ibn al-Jazari (may Allah have mercy on him) thought that this view was more
likely to be correct when he said in an-Nashr fi’l-Qiraa’aat al-‘Ashr
(1/19): 

The correct view in our opinion is that the matter requires further
discussion, so as to find a middle path. We say that if switching modes of
recitation in a single verse would affect the meaning or render it
incomprehensible, then in this case it is disallowed in the sense of being
prohibited, such as when there is a sentence in which switching modes of
recitation would change the case of a word from nominative to accusative, or
vice versa, and could lead to there appearing to be two subjects or two
objects in a single sentence (thus rendering it meaningless and contravening
the rules of grammar). But if that is not the case, then we should
differentiate between cases where the reciter claims that this is a mode of
recitation or otherwise. If he recites it in this manner and claims that
this is one of the modes of recitation, then it is not permissible because
he is lying about that mode of recitation and it is confusing to people who
have knowledge of recitation. If he is not claiming that this is a mode of
recitation, rather it happened that he recited it this way, then it is
permissible, valid and acceptable, and there is nothing wrong with it and it
is not prohibited, even though we do not accept it from people who have
knowledge of the different modes of recitation, because it is not acceptable
for scholars to recite the Qur’an in the manner of people who have no
knowledge, not because it is makrooh or haraam, because it is all from Allah
and was brought down by the Trustworthy Spirit to the heart of the leader of
the Messengers, to make it easy for the ummah and the people of this
religion. If we had to require them all to recite according to one
particular mode of recitation, it would be difficult for them to stick to
one mode of recitation, and the aim of making things easy would be turned on
its head. End quote. 

3.

The third view is that of those scholars who disallowed it. Ibn al-Jazari
said in an-Nashr fi’l-Qiraa’aat al-‘Ashr (1/18):

Therefore some scholars regarded it as wrong for a reciter to mix the
different modes of recitation with one another, whether in a Sunnah or
obligatory prayer. Imam Abu’l-Hasan ‘Ali ibn Muhammad as-Sakhaawi said in
his book Jamaal al-Qurraa’: Mixing these modes of recitation together
is wrong.  End quote. 

It seems – and Allah knows best – that what is more correct with regard to
this issue is to differentiate between the one who prays on his own, who may
combine two or more recitations in one prayer, subject to the conditions
mentioned by an-Nawawi and Ibn al-Jazari, and one who prays as an imam,
leading people in prayer; in that case he should not do that, because
reciting more than one mode of recitation in one rak‘ah may lead to
confusion for the worshippers and may cause disputes and disagreements among
them; in fact if he recites in a mode of recitation other than that which
the people are used to, it may cause confusion. 

It says in Fataawa al-Lajnah ad-Daa’imah (4/26), in the third
question of fatwa no. 7339: 

Is it permissible to recite Qur’an in prayer according to the recitation of
Warsh, knowing that we usually recite according to the recitation of Hafs
(that was transmitted) from ‘Aasim? 

The answer was: reciting according to the mode of recitation of Warsh (that
was transmitted) from Naafi‘ is valid in and of itself according to the
scholars of recitation, but reciting in this mode of recitation for those
who are not used to it, and are used to something else – such as the
recitation that was transmitted from Hafs, for example – may cause confusion
in the worshippers, so it should not be done for that reason. But if the one
who is reciting according to this mode of recitation is praying on his own,
then it is permissible, because there is no reason not to do that. End
quote. 

And Allah knows best.