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(PBUH), 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)." Translation Not Available
Book Ref: Sunan Ibn Majah Book 33 Hadith 3708
Web Ref: Sunan Ibn Majah Vol 5 Book 33 Hadith 3708