Hadith 3708
Chapter 17: Seeking Permission to Enter - كتاب الأدب
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا أَبُو بَكْرِ بْنُ عَيَّاشٍ، عَنْ مُغِيرَةَ، عَنِ الْحَارِثِ، عَنْ عَبْدِ اللَّهِ بْنِ نُجَىٍّ، عَنْ عَلِيٍّ، قَالَ كَانَ لِي مِنْ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ مُدْخَلاَنِ مُدْخَلٌ بِاللَّيْلِ وَمُدْخَلٌ بِالنَّهَارِ فَكُنْتُ إِذَا أَتَيْتُهُ وَهُوَ يُصَلِّي يَتَنَحْنَحُ لِي .
It was narrated that Ali said:
"I had two times of visiting the Messenger of Allah(ﷺ), at night and during the day. If I came to him when he was praying, he would clear his throat (to let me know he was praying)."
Reference : Sunan Ibn Majah 3708
In-book reference : Book 33, Hadith 52