We have a custom at the end of the prayer, especially the Fajr and Maghrib prayers, where after the imam says the taslim and finishes his prayer, and before he turns to the worshippers, he reads

The questioner : We have a custom at the end of the prayer, especially the Fajr and Maghrib prayers, where after the imam says the taslim and finishes his prayer, and before he turns to the worshippers, he, or the mu'adhdhin, or one of the worshippers, for example, reads: to the end. Then he says in a low voice: "O Allah, send blessings upon him," and the other worshippers do the same, up to a number that may reach approximately one hundred. After that, he reads only the Verse of the Throne, then the tasbih, tahmid, and takbir. Then he says: "There is no god but Allah, Muhammad is the Messenger of Allah. There is no god but Allah alone, with no partner." Then he supplicates at the top of his voice, raising his hands, and all the worshippers do so in a low voice. The observation, O Shaykh, he says, is that the imam, or whoever takes his place at the end of the prayer, supplicates aloud, while the other worshippers supplicate in a low voice or say "Ameen" to the supplication in a low voice. Is this manner of concluding the prayer established in the Shari'ah? Please inform us, may you be rewarded.

The Shaykh : Praise be to Allah, Lord of the worlds, and may Allah send blessings and peace upon our Prophet Muhammad, and upon his family and his Companions, and those who follow them with excellence until the Day of Resurrection. This manner is not established in the Islamic Shari'ah. Rather, the Prophet (peace and blessings be upon him), when he said the taslim from his prayer, would seek forgiveness three times and say: as well as the other dhikr established from the Prophet (peace and blessings be upon him).
As for this manner, it is a reprehensible and ugly religious innovation (bid'ah) that deviates from what the Prophet (peace and blessings be upon him) guided us to. It is obligatory for these people to repent to Allah (Mighty and Majestic) and to return to the guidance of the Messenger of Allah (peace and blessings be upon him), which is available, praise be to Allah, in the books of hadith and in the books of jurists. It should be known that whoever persists in an innovation after knowing it will not increase thereby except in misguidance and distance from Allah (Mighty and Majestic). We hope that Allah (Glorified and Exalted is He) will guide our Muslim brothers to the path of those upon whom Allah has bestowed favor, from the prophets, the truthful, the martyrs, and the righteous.
And the ma'mum (worshippers behind the imam), we call upon them and urge them not to pay attention to this. When they say the taslim, they should seek forgiveness three times and say: "O Allah, You are Peace, and from You is peace. Blessed are You, O Owner of Majesty and Honor" and they should recite the dhikr established from the Prophet (peace and blessings be upon him) and then leave, leaving the imam alone. If it happens that the imam himself returns to the Sunnah and reads the hadiths established from the Prophet (peace and blessings be upon him) in this regard, then he will thereby be an imam for the righteous, because his action, which I mean his return from the innovation to the Sunnah, is from the mindfulness of Allah (Mighty and Majestic). People will follow their imams, so he will thereby be an imam for the righteous. I ask Allah to guide us all to what is good and righteous, and to guide us to His straight path, the path of those upon whom Allah has bestowed favor, from the prophets, the truthful, the martyrs, and the righteous.

The questioner : May Allah reward you with good, O Shaykh. The questioner says, this questioner says.