He sneezed whilst he was praying – should he say al-hamdu Lillaah?
Question

                If I sneeze whilst I am praying, should I say al-hamdu Lillaah or not?.
Praise be to Allah.
    If a person sneezes whilst he is praying, it is prescribed 
    for him to say al-hamdu Lillaah, may He be glorified, whether the prayer is 
    obligatory or naafil. This is the view of the majority of scholars among the 
    Sahaabah and Taabi’een, and it was also the view of Imam Maalik, al-Shaafa’i 
    and Ahmad, but they differed as to whether he should say it silently or out 
    loud. The correct view and the view of Imam Ahmad is that he should say it 
    out loud, but only loud enough that he can hear himself, lest he distract 
    other worshippers. That is indicated by the general meaning of the report 
    narrated by Abu Hurayrah (may Allaah be pleased with him), that the Prophet 
     (peace and blessings of Allaah be upon him) said: “If one of you 
    sneezes, let him say ‘Al-hamdu Lillaah’…” The hadeeth was narrated by 
    al-Bukhaari. That is also supported by the report narrated by Rifaa’ah ibn 
    Raafi’ (may Allaah be pleased with him) who said: I prayed behind the 
    Messenger of Allaah  (peace and blessings of Allaah be upon him) and I 
    sneezed and said: Praise be to Allaah, much good and blessed praise, as our 
    Lord loves and is pleased with. When the Messenger of Allaah  (peace and 
    blessings of Allaah be upon him) had finished praying he said: “Who is the 
    one who spoke during the prayer?” and no one said anything. Then he said it 
    a second time, “Who is the one who spoke during the prayer?” and no one said 
    anything. Then he said it a third time, “Who is the one who spoke during the 
    prayer?” and Rifaa’ah ibn Raafi’ said: It was me, O Messenger of Allaah. He 
    said: “What did you say?” He said: I said: Praise be to Allaah, much good 
    and blessed praise, as our Lord loves and is pleased with. The Messenger of 
    Allaah  (peace and blessings of Allaah be upon him) said: “By the One in 
    Whose hand is my soul, thirty-odd angels competed to see which of them would 
    take it up.” Narrated by al-Tirmidhi, Abu Dawood and al-Nasaa’i. Al-Tirmidhi 
    said: a hasan hadeeth. Al-Haafiz narrated in al-Tahdheeb from 
    al-Tirmidhi that it is saheeh. It was also narrated by al-Bukhaari in his 
    Saheeh but he did not mention that he said that after sneezing, rather 
    he said it after rising from bowing. It may be that he sneezed whilst rising 
    from bowing and he said that because he sneezed, and the Prophet  (peace 
    and blessings of Allaah be upon him) approved of that and did not rebuke him 
    for it. This indicates that it is prescribed during prayer, but if a person 
    sneezes whilst praying then praises Allaah, it is not permissible for those 
    who hear him to say Yarhamak Allaah (may Allaah have mercy on you), because 
    that is part of human speech and it is not permissible during prayer. It is 
    proven that the Prophet  (peace and blessings of Allaah be upon him) 
    denounced someone who said Yarhamak Allaah to a man who sneezed whilst 
    praying, then he said to him: “In this prayer nothing of human speech is 
    permitted; it is only tasbeeh (glorifying Allaah), takbeer (magnifying 
    Allaah) and recitation of Qur’aan.” Narrated by Imam Muslim, Abu Dawood and 
    al-Nasaa’i. 

    And Allaah is the Source of strength. May Allaah send 
    blessings and peace upon our Prophet Muhammad and his family and companions. 
    End quote. 

    Standing Committee for Academic Research and Issuing Fatwas.