I had two times when I would enter upon the Messenger of Allah ﷺ, one at night and one during the day. Whenever I came to him while he was praying, he would clear his throat to signal me.
حدثنا أبو بكر بن أبي شيبة حدثنا أبو بكر بن عياش عن مغيرة عن الحارث عن عبد الله بن نجي
كان لي من رسول الله ﷺ مدخلان مدخل بالليل ومدخل بالنهار فكنت إذا أتيته وهو يصلي يتنحنح لي
[Sahih]. Nasai reported it in the chapter on inattentiveness, "Clearing the throat during prayer," 12/3, no. 1213, from the hadith of Abu Bakr bin Ayyash, and Jareer corroborated him, as found in his version, and the hadith is also in Musannaf, 420/8. Harith Ukli was corroborated by Shurahbil bin Mudrik, who is trustworthy, from Abdullah bin Naji, from his father, from Ali, with the same wording. Nasai, no. 1212, and see also no. 3650.