Their saying “O Allaah, send blessings upon Muhammad as much as the perfection of Allaah”
Question

                There is a custom in the mosque, where after praying in congregation and straight after reciting tasbeeh (“Subhaan-Allaah”), tahmeed (“al-hamdu Lillaah”) and takbeer (“Allaahu akbar”), they repeat salawaat (blessings upon the Prophet (peace and blessings of Allaah be upon him)) following the muezzin, in three different forms, as follows:  

1-    “O Allaah, send blessings and peace and bless our master Muhammad and his family, as much as the perfection of Allaah and as befits His perfection.”

2-    “O Allaah, send blessings and peace and bless our master Muhammad and his family, as much as the names of Allaah and as befits His perfection.”

3-    And they recite al-Salawaat al-Ibraaheemiyyah which is well known. 

Please note that there are those who say that the phrase “as much as the perfection of Allaah” is not permissible, as mentioned in the first version, on the grounds that it is limiting the perfection of Allaah, but they regard the phrase “as much as the names of Allaah” as permissible, as in the second version. What is your opinion of all these versions? May Allaah reward you with good.
Praise be to Allah.
    Firstly: 

    Among the adhkaar that are prescribed after prayer are:  
    tasbeeh (“Subhaan-Allaah”), tahmeed (“al-hamdu Lillaah”), takbeer (“Allaahu 
    akbar”) and tahleel (“laa ilaaha ill-Allaah”), because of the report 
    narrated by Muslim (596) from Ka’b ibn ‘Ujrah , that the Messenger of Allaah 
     (peace and blessings of Allaah be upon him) said: “Dhikrs after the 
    prayer, the one who says them or does them will not be disappointed: 
    thirty-three tasbeehahs, thirty-three tahmeedahs and thirty-four takbeerahs 
    after every prayer.” 

    Muslim also narrated (597) from Abu Hurayrah that the 
    Messenger of Allaah  (peace and blessings of Allaah be upon him) said: 
    “Whoever glorifies Allaah thirty-three times after every prayer, and praises 
    Allaah thirty-three times, and magnifies Allaah thirty-three times, making 
    ninety-nine, and completes it by saying, ‘There is no god but Allaah alone, 
    with no partner or associate; His is the Dominion, to Him be praise, and He 
    is Able to do all things,’ his sins will be forgiven even if they are like 
    the foam of the sea.” 

    In al-Saheehayn it is narrated from Abu Hurayrah that 
    the poor among the Muhaajireen came to the Messenger of Allaah  (peace 
    and blessings of Allaah be upon him) and said: The people of great wealth 
    have taken the highest ranks and eternal bliss. He said: “Why is that?” They 
    said: They pray as we pray and they fast as we fast, but they give in 
    charity and we do not, and they free slaves and we do not. The Messenger of 
    Allaah (S) said: “Shall I not teach you something by means of which you may 
    catch up with those who have gone ahead of you and go ahead of those who 
    come after you, and there will be no one who is better than you except those 
    who do as you do?” They said: Yes, O Messenger of Allaah. He said: “Glorify 
    Allaah, magnify Him and praise Him at the end of every prayer, thirty-three 
    times.” Abu Saalih said: The poor Muhaajreen went back to the Messenger of 
    Allaah (S) and said: Our wealthy brothers have heard what we did and they 
    did likewise. The Messenger of Allaah (S) said: “That is a bounty from 
    Allaah; He gives it to whomever He wills.”

    Al-Bukhaari (843) and Muslim (595). 

    This great dhikr should be recited by each person 
    individually. Reciting it in unison, led by the muezzin or imam or anyone 
    else is a bid’ah (innovation), because it is a manner that is not narrated 
    from the Prophet  (peace and blessings of Allaah be upon him), and the 
    scholars have drawn attention to that. 

    Al-Shaafa’i (may Allaah have mercy on him) said: I think that 
    the imam and the person praying behind him should remember Allaah after they 
    finish the prayer and they should recite the dhikr quietly, unless he is the 
    imam who should be learned from, in which case he may recite it out loud 
    until he thinks that they have learned from him, then he should recite it 
    quietly. Allaah says (interpretation of the meaning):  

    “And offer your Salaah (prayer) neither aloud nor in a low 
    voice”

    [al-Isra’ 17:110]

    This refers – and Allaah knows best – to du’aa’ 
    (supplication), which should be recited “neither aloud” in a loud voice nor 
    “in a low voice” such that you cannot hear yourself.  

    The evidence for that is what Ibn al-Zubayr narrated about 
    the tahleel of the Prophet  (peace and blessings of Allaah be upon him) 
    and what Ibn ‘Abbaas narrated about his takbeer, as we have quoted above. 
    Al-Shaafa’i said: 

    I think that he may raise his voice a little in order for the 
    people to learn from him, because most of the reports that we have written 
    here and elsewhere do not mention reciting tahleel or takbeer after the 
    salaam. End quote from al-Umm (1/127). 

    Al-Shaatibi (may Allaah have mercy on him) said: Bid’ah 
    (innovation) refers to something that is newly invented in matters of 
    religion that appears similar to that which is prescribed, by which people 
    intend to go to extremes in worshipping Allaah, may He be glorified. That 
    includes adhering to certain forms of worship, such as reciting dhikr in a 
    group, in unison, or taking the day of the Prophet’s birth as a festival, 
    and so on. 

    That also includes adhering to certain acts of worship at 
    certain times, for which there is no evidence in sharee’ah, such as always 
    fasting on the fifteenth of Sha’baan (al-nusf min Sha’baan) and spending 
    that night in prayer. End quote from al-I’tisaam (1/37-39). 

    Shaykh Jamaal al-Deen al-Qaasimi (may Allaah have mercy on 
    him) said: In some mosques, when the imam says the salaam at the end of the 
    obligatory prayer of ‘Asr, the muezzin shouts ameen and recites a du’aa’ 
    loudly after that, and in some mosques when the imam says the salaam, the 
    followers  start to recite blessings on the Prophet  (peace and 
    blessings of Allaah be upon him) with “al-salaah al-kamaaliyyah” [the format 
    referred to in the question] out loud. This is contrary to sharee’ah, 
    because the Sunnah is, immediately after the prayer, to recite silently the 
    du’aa’s that have been narrated, each worshipper reciting by himself. 
    Similarly, the etiquette of du’aa’ is to keep the voice low. Allaah says 
    (interpretation of the meaning): 

    “Invoke your Lord with humility and in secret”

    [al-A’raaf 7:55]

    These people are turning away from humility and secrecy by 
    means of their shouting and yelling. End quote from Islaah al-Masaajid 
    min al-Bida’ wa’l-‘Awaa’id, p. 154. 

    Shaykh ‘Ali Mahfooz (may Allaah have mercy on him) said: A 
    kind of reprehensible bid’ah is ending the prayer in the well known manner, 
    raising the voice with the du’aa’ in the mosque, reciting it in unison and 
    doing it regularly, to the extent that a lot of people think that this is 
    part of praying properly, and that it is Sunnah and is essential, although 
    it is mustahabb to recite du’aa’ individually and quietly. 

    This format is innovated, and it is not known from the 
    Messenger of Allaah  (peace and blessings of Allaah be upon him) or from 
    the Sahaabah. The people have taken it as a part of the obligatory prayer, 
    to be done after praying in congregation. 

    How can it be permissible to raise one's voice in reciting 
    it, when Allaah, may He be exalted, says in His wise Book (interpretation of 
    the meaning): 

    “Invoke your Lord with humility and in secret. He likes 
    not the aggressors”

    [al-A’raaf 7:55]? 

    Reciting quietly is closer to sincerely and further-removed 
    from showing off. End quote from al-Ibdaa’ fi Madaar al-Ibtidaa’, p. 
    283. 

    In Fataawa al-Lajnah al-Daa’imah (7/98) it says: 

    Question: The people differed with regard to reciting du’aa’ 
    in unison after the regular Sunnah prayers. One group says that there is no 
    report concerning that from the Prophet  (peace and blessings of Allaah 
    be upon him) or from the Sahaabah, and if it was good they would have done 
    it before us, because they were the keenest of people to follow the truth. 
    Another group says that reciting du’aa’ in unison after the regular Sunnah 
    prayers is mustahabb and even Sunnah because it is dhikr and worship and no 
    dhikr or worship can be anything less than mustahabb and Sunnah. They 
    criticize those who do not wait for the du’aa’ and get up straight after 
    praying. 

    Answer: Du’aa’ is an act of worship, and acts of worship are 
    based on tawqeef (adhering only to that which is mentioned in Qur’aan and 
    Sunnah). So it is not permissible to say that an act of worship is 
    prescribed – with regard to its principle, number, form or place except with 
    proper shar’i evidence. We do not know of any Sunnah concerning that which 
    was narrated from the Prophet  (peace and blessings of Allaah be upon 
    him), whether in word or deed, or his approval, which would point to the 
    claim made by the second group. All goodness is in following the guidance of 
    the Prophet  (peace and blessings of Allaah be upon him), and his 
    guidance with regard to this matter is proven with evidence of what he  
    (peace and blessings of Allaah be upon him) used to do after prayer, and 
    what his successors (the caliphs) and companions and the Taabi’een and those 
    who followed them in goodness also used to do. Whoever introduces anything 
    that goes against the guidance of the Messenger  (peace and blessings of 
    Allaah be upon him) will have it rejected. The Prophet  (peace and 
    blessings of Allaah be upon him) said: “Whoever does any deed that is not in 
    accordance with this matter of ours will have it rejected.” The imam who 
    says du’aa’ after the prayer and the congregation says ameen to his du’aa’, 
    all of them raising their hands, should be asked for evidence to support his 
    action, otherwise it is to be rejected, The same applies to one who does 
    that after naafil prayers; he should be asked for evidence as Allaah says 
    concerning such things (interpretation of the meaning): 

    “Say (O Muhammad), Produce your proof if you are truthful”

    [al-Baqarah 2:111]

    We do not know of any evidence from the Qur’aan or Sunnah 
    which suggests that what the second group claims is prescribed in Islam, 
    namely reciting du’aa’ together and reciting dhikr in the manner mentioned 
    in the question. End quote. 

    Conclusion: Reciting dhikr in unison, whether it is tasbeeh 
    or blessings upon the Prophet  (peace and blessings of Allaah be upon 
    him) – in any form – is not Sunnah, rather it is a bid’ah and innovation. 

    Secondly: 

    Al-salaah al-kamaaliyyah, which is “O Allaah, send blessing 
    and peace and bless our master Muhammad and his family, as much as the 
    perfection of Allaah and as befits His perfection” is not narrated from the 
    Prophet  (peace and blessings of Allaah be upon him) or from any of his 
    companions (may Allaah be pleased with them), and it is not the best form of 
    sending blessings upon the Prophet  (peace and blessings of Allaah be 
    upon him) as some people think. Rather the best form of sending blessings is 
    that which the Prophet  (peace and blessings of Allaah be upon him) 
    taught to his companions, which is al-salaah al-Ibraaheemiyyah. 

    al-Bukhaari (6357) and Muslim (406) narrated that ‘Abd 
    al-Rahmaan ibn Abi Layla said: Ka’b ibn ‘Ujrah met me and said: Shall I not 
    give you a gift? The Messenger of Allaah  (peace and blessings of Allaah 
    be upon him) came out to us and we said, We know what it means to send 
    salaam upon you, but what does it mean to send blessings upon you? He said: 
    “Say: Allaahumma salli ‘ala Muhammadin wa ‘ala aali Muhammadin kama 
    salayta ‘ala aali Ibraaheem, innaka hameedun majeed; Allaahumma baarik ‘ala 
    Muhammadin wa ‘ala aali Muhammadin kama baarakta ‘ala aali Ibraaheem, innaka 
    hameedun majeed (O Allaah, send Your salaah (grace, honour and 
    mercy) upon Muhammad and upon the family of Muhammad, as You sent Your 
    salaah upon the family of Ibraaheem, You are indeed Praiseworthy, Most 
    Glorious. O Allaah, send Your blessings upon Muhammad and the family of 
    Muhammad, as You sent Your blessings upon the family of Ibraaheem, You are 
    indeed Praiseworthy, Most Glorious).” 

    Al-Bukhaari (3369) and Muslim (407) narrated from Abu Humayd 
    al-Saa’idi (may Allaah be pleased with him) that they said: O Messenger of 
    Allaah, how should we send blessings upon you? He said: “Say: Allaahumma 
    salli ‘ala Muhammadin wa ‘ala azwaajihi wa dhurriyyatihi kama salayta ‘ala 
    Ibraaheem, wa baarik ‘ala Muhammadin wa ‘ala azwaajihi wa dhurriyyatihi kama 
    baarakta ‘ala aali Ibraaheem, innaka hameedun majeed (O Allaah, send 
    Your salaah (grace, honour and mercy) upon Muhammad and upon his 
    wives and offspring, as You sent Your salaah upon Ibraaheem, and send 
    Your blessings upon Muhammad and upon his wives and offspring, as You sent 
    Your blessings upon the family of Ibraaheem. You are indeed Praiseworthy, 
    Most Glorious).” 

    Al-Suyooti (may Allaah have mercy on him) said in al-Haraz 
    al-Manee’: I read in al-Tabaqaat by al-Taaj al-Subki a quotation 
    from his father that said: The best manner of sending blessings upon the 
    Prophet  (peace and blessings of Allaah be upon him) is the way that is 
    mentioned in the Tashahhud. 

    He said: Whoever says this has definitely sent blessings upon 
    the Prophet  (peace and blessings of Allaah be upon him), but whoever 
    says any other version, there is some doubt as to whether he has recited the 
    blessings as required, because they said: “How should we send blessings upon 
    you?” and he said: “Say…” so he stated that blessings upon him should be 
    sent by saying that. 

    Al-Suyooti said: When I grew old, when I sent blessings upon 
    the Prophet  (peace and blessings of Allaah be upon him) I would say: O 
    Allaah, send blessings and peace upon Muhammad and upon the family of 
    Muhammad as You sent blessings and peace upon Ibraaheem and upon the family 
    of Ibraaheem. You are indeed Praiseworthy, Most Glorious. It was said to me 
    in a dream: Are you more knowledgeable of the meaning of words and more 
    eloquent than the Prophet  (peace and blessings of Allaah be upon him)? 
    If there was not some extra meaning in the version spoken by the Prophet 
     (peace and blessings of Allaah be upon him) he would not have preferred 
    that? So I asked Allaah for forgiveness for that, and I went back to the 
    preferred version at times when it is obligatory and mustahabb. 

    And he said: If a person has sworn to send blessings upon him 
    in the best manner, then the best thing is to do that. End quote from 
    al-Sunan wa’l-Mutada’aat by Muhammad ‘Abd al-Salaam al-Shuqayri, p. 232. 
    The words of al-Taaj al-Subki appear in Tabaqaat al-Shaafa’iyyah al-Kubra 
    (1/185). 

    Thirdly: 

    Al-salaah al-kamaaliyyah contains something that goes against 
    sharee’ah, when it says “as much as the perfection of Allaah”. The apparent 
    meaning of the phrase (in Arabic, ‘adada kamal Allaah) is that the 
    perfection of Allaah, may He be exalted, is limited by number. Hence some of 
    the scholars stated that this prayer is not allowed, as we shall see below. 
    The same applies to their saying “the number of the names of Allaah”, 
    because the names of Allaah are not limited to a specific number, as the 
    Prophet  (peace and blessings of Allaah be upon him) said: “I ask You by 
    every name by which You have called Yourself or You have taught to anyone of 
    Your creation or You have revealed in Your Book or You have kept secret in 
    the knowledge of the Unseen which is with You.” Narrated by Ahmad (3704). 

    Ibn ‘Aabideen (may Allaah have mercy on him) said in his 
    Haashiyah (6/396): You should avoid using such phrases as “O Allaah, 
    send blessings upon Muhammad as much as Your knowledge and forbearance, to 
    the extent of Your mercy, as many as Your Words, and much as the perfection 
    of Allaah,” and so on, because this may suggest than a divine attribute has 
    many forms or that there is a limit to His knowledge, especially phrases 
    such as “as much as Your knowledge,  as much as You can hear,as much as Your 
    words”, because there is no limit to His knowledge or mercy, or to His 
    words. The word ‘adad (translated as “as much as” or “as many as”) etc 
    suggests something other than that. I read the commentary by al-‘Allaamah 
    al-Fasi on the book Dalaa’il al-Khayraat, where he discussed this issue. He 
    said: The scholars differed as to whether it is permissible to use phrases 
    that may be misinterpreted for those who will not misinterpret them, or to 
    use phrases that may be easily interpreted in the proper manner. A number of 
    scholars selected certain ways of sending blessings on the Prophet  
    (peace and blessings of Allaah be upon him) and said that they are the best 
    ways of sending blessing, such as Shaykh ‘Afeef al-Deen al-Yaafa’i, 
    al-Sharaf al-Baarazi and al-Baha’ ibn al-Qattaan, and it was narrated from 
    him by his student al-Maqdisi. End quote. I say: the words of our imams 
    imply that that is not allowed, except in the words narrated from the 
    Prophet  (peace and blessings of Allaah be upon him), according to the 
    view favoured by the faqeeh. And Allaah knows best. End quote. 

    As stated above, the manner of sending blessing that you 
    mentioned is not Sunnah, even if it is reciting al-salaah 
    al-Ibraaheemiyyah. 

    May Allaah help us and you to do that which He loves and 
    which pleases Him. 

    And Allaah knows best.