Arabic (Original)
وَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا قُلْتَ لِلنَّاسِ أَنْصِتُوا وَهُمْ يَتَكَلَّمُونَ فَقَدْ أَلْغَيْتَ عَلَى نَفْسِكَ.
English Translation
The Messenger of Allah (peace be upon him) said: 'If you say to people "Be quiet" while they are talking, you have committed an idle act yourself.'