The Prophet sallallaahu ‘alaihi wasallam said:
إذا قلتَ للناسِ أَنصِتوا و هم يتكلَّمون ، فقد ألْغَيْتَ على نفسِك
“If you say ‘shut up’ to the people while they are talking, you’re really reproaching yourself” (HR Ahmad 2/318, Al Albani said this hadits is shahih [Silsilah Ash Shahihah, 1/328]).
This hadith originally spoke about the prohibition of speaking when khatib performing Friday khutbah. But Noble Shaikh Muhammad Nashiruddin Al Albani said:
“In this hadith there is also a warning against the lack of the application of adab that is good in speaking and talking with people. That is, someone should not cut off the conversation of others when they are talking, he should be quiet and wait for them to finish speaking, even though he is a figure in his people.
After the talk is finished, then it is his turn to speak if he wants. With this manner, more information is conveyed from the words spoken in order to discuss the problem between the two parties. Even more so when discussing about Islamic knowledge. But it is very unfortunate that many people discuss a problem they forgot about this behaviour. They should give a big attention to this goog behaviour, which the Prophet Sallallahu’alaihi Wasallam taught us” (Silsilah Al Ahadits As Sahihah, 1/329).