"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."
قُلْنَا يَا رَسُولَ اللَّهِ هَذَا السَّلاَمُ فَمَا الاِسْتِئْنَاسُ قَالَ يَتَكَلَّمُ الرَّجُلُ تَسْبِيحَةً وَتَكْبِيرَةً وَتَحْمِيدَةً وَيَتَنَحْنَحُ وَيُؤْذِنُ أَهْلَ الْبَيْتِ