Dhikr (mentioning the name of Allah) in a loud voice after obligatory prayers was (a common practice) during the lifetime of the Messenger of Allah (ﷺ) ; and when I heard that I came to knew that they (the people) had finished the prayer.
Reference: Sahih Muslim 583 c In-book : Book 5, Hadith 156 USC-MSA web (English) : Book 4, Hadith 1211 (deprecated)
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