(17) باب الاِسْتِئْذَانِ
It was narrated that Abu Ayyub Ansari said:
"We said: 'O Messenger of Allah(ﷺ), (we know) this (greeting of) Salam, but what does seeking permission to enter mean?' He said: 'It means a man saying SubhanAllah, and Allahu Akbar and Al Hamdulillah, and clearing his throat, announcing his arrival to the people in the house."
Reference: Sunan Ibn Majah 3707
In-book reference: Book 33, Hadith 51
English translation: Vol. 5, Book 33, Hadith 3707