Fiqh-us-Sunnah Volume 4, Funerals and Dhikr, Fiqh 4.056A.

Recite or raise one’s voice or any similar activity. Ibn Al-Munzhir related that Qais ibn ‘Abbad said: “The Companions of the Prophet, peace be upon him, disliked raising one’s voice on three occasions, namely, funeral processions, when remembering Allah, and on the battlefield.”

Sa’id ibn Al-Musaib, Sa’id ibn Jubair, Al-Hasan, An-Nakh’i, Ahmad, and Ishaq did not like it when anyone from the rear of the funeral procession exhorted others to pray for forgiveness of the deceased. Al-Awza’i said: This is a bid’a (innovation in religion). Fuzhail ibn ‘Amr said: “Once, while Ibn ‘Umar was present at a funeral, he heard someone from behind saying: ‘Pray for Allah’s forgiveness for the deceased. May Allah forgive him.’ Ibn ‘Umar said: ‘May Allah not forgive you’.”

An-Nawawi said: “You should know that the right manner of accompanying a funeral procession is to remain quiet, as the pious among the previous generations of Muslims did. One should not raise one’s voice for recitation or for the remembrance of Allah, or for anything else. Keeping quiet is better and is helpful in concentrating one’s attention on the funeral rites, which is needed at that time. This is the correct position, and the fact that a large number of people do otherwise does not change it. There is a consensus among scholars that the way ignorant people recite in the funeral processions, artificially prolonging sounds of various words and mixing them up, is forbidden.

Mohammad ‘Abduh issued a verdict concerning raising one’s voice for the remembrance of Allah while following the funeral procession, in which he said: “In reference to the raising of one’s voice in a funeral procession for remembrance of Allah, we find in Al-Fath, under the chapter on “Funerals,” that it is disliked for a person walking in front of a funeral procession to make such remembrance loudly. If one wants to make any remembrance, one may do it in one’s heart. Loud remembrance is something quite new, and there is no precedent for it from the days of the Prophet, peace be upon him, and his Companions, or from the generation following them or their Successors. Such a practice must be discouraged and stopped.”