Ruling on Collective Dhikr After the Prayers

Question

You said it is permissible to raise the voice in remembrance after the prayer — but if this results in the remembrance becoming collective among the worshippers, is that permissible?

Answer (English translation)

In reality, I did not say it is permissible — I said it is from the Sunnah, meaning: preferable. It is from the Sunnah without doubt.

As for performing this remembrance collectively (in unison), that is an innovation, because the Messenger (peace and blessings be upon him) and his Companions did not do that: each person remembered Allah on his own, though they did so aloud.