´It was narrated that Abu Ma’mar said:` “I said to Khabbab: ‘How did you recognize that the Messenger of Allah (ﷺ) was reciting in the Zuhr and the ‘Asr?’ He said: ‘From the movement of his beard.’”
Hadith ReferenceSunan Ibn Majah / Establishing the Prayer and the Sunnah Regarding Them / Hadith: 826
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:صحيح بخاري