Abu Dawud

1003. Commentary:
After the salam, saying «الله اكبر» and «استغرالله» three times, as well as some other phrases—especially in a raised voice—is an established Sunnah. It is not correct to interpret this as something to be done only occasionally or merely for the purpose of teaching. However, it is necessary that the raising of the voice should not be to such an extent that it causes disturbance or confusion for others.

Hadith Commentary:

And Ibn Abbas said:
I used to know when they had finished (the prayer) by hearing that (remembrance). Ibn Abbas (radi Allahu anhu) said that by hearing the remembrance (dhikr), I would understand that the people had completed their prayer.

Hadith Commentary:
In the hadith, the virtue of remembrance (dhikr) after the prayer is transmitted, but what is meant by this remembrance? In the present era, the collective and loud chanting of "Allah" after the prayer, as is commonly practiced, is absolutely an un-Islamic act. Rather, what is meant here is saying "Allahu Akbar," as will be clarified in the following hadith.

Hadith Commentary: Benefits and Issues:

It is established from the narration of Ibn Abbas radi Allahu anhuma that during the blessed era of the Messenger of Allah sallallahu alayhi wa sallam, after concluding the obligatory prayer with salam, dhikr would be recited aloud. The clarification of this dhikr is given in another narration as takbir. From this, it is understood that those following the prayer behind the Prophet sallallahu alayhi wa sallam would also say "Allahu Akbar" aloud. And it is narrated from Abdullah bin Zubair radi Allahu anhuma that after salam, the Prophet sallallahu alayhi wa sallam would say aloud:

(La ilaha illallahu wahdahu la sharika lahu,
lahul-mulku,
walahul-hamdu,
wahuwa ‘ala kulli shay’in qadeer,
la hawla wa la quwwata illa billah,
la ilaha illallah,
wa la na‘budu illa iyyahu,
lahu an-ni‘matu walahul-fadlu walahuth-thana’ul-hasan,
la ilaha illallahu mukhliseena lahud-deena walaw karihal-kafiroon)

From this, the permissibility of the currently practiced loud dhikr is not established. What is only established is that after the salam, the Prophet sallallahu alayhi wa sallam would say these words aloud so that those near him could hear, and those near him, following his lead, would also say them, and in this way, the sound would reach the last row, where Ibn Abbas radi Allahu anhuma, who was among the children, would be present.

However, nowadays, instead of reciting the prescribed words aloud, people recite some words of their own invention in unison and in one voice. How can the proof of such harmony be derived from this narration? Allamah Saeedi has quoted from Allamah Shami rahimahullah that collective dhikr in mosques is considered commendable by both the predecessors and successors, provided that their loudness does not disturb anyone’s sleep, recitation, or prayer. Can this statement be used as evidence for the current form of loud dhikr?