Our Shaikh, Imaam Wadiee (رحمه الله), was asked as mentioned in (the book) “Ghaarah Ashritah” (Vol. 2 pgs. 245-246) about saying dhikr collectively with one voice.
So the Shaikh answered: ” (Saying it) in one voice while raising the voices, this has not been established by the Prophet (ﷺ), and at times something may be legislated and then people add to it that which corrupts it, similar to the manner (mentioned in the question).
And Imaam Ibn Baz (رحمه الله) was asked as it came in “Fatawa Nur ala’ Darb” (Vol. 9 pgs. 483-484): “We have a custom here in Ramadan where after the Taraweeh prayer we make dua collectively and those praying repeat it and end their prayers with it. What is the ruling of this action?
So the Shaikh answered: … This is an innovation, there is no dhikr, nor dua that is done collectively. Every person should make dua for himself and for the Muslims. (His dua) is between him and his Lord -the Exalted, and the dua is not done collectively, nor is the dhikr.
Answered by: Shaikh Abu Abdillah Muhammad Ba Jamaal (May Allah preserve him)
Source: Jaamiah al-Farid fee Mukaalafaat sharh Ramadan wa Eid
Translated by: Abu Yusuf Bilal ibn Howard Robinson