حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا عَبْدُ الْوَاحِدِ بْنُ زِيَادٍ، عَنِ الأَعْمَشِ، عَنْ عُمَارَةَ بْنِ عُمَيْرٍ، عَنْ أَبِي مَعْمَرٍ، قَالَ قُلْنَا لِخَبَّابٍ هَلْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَقْرَأُ فِي الظُّهْرِ وَالْعَصْرِ قَالَ نَعَمْ ‏.‏ قُلْنَا بِمَ كُنْتُمْ تَعْرِفُونَ ذَاكَ قَالَ بِاضْطِرَابِ لِحْيَتِهِ ‏.‏

Abu Ma’mar said: We asked Khabbab: Did the Messenger of Allah (PBUH) recit (the Quran) in the noon and afternoon prayers? He replied: Yes. We then asked: How did you know this? He said: By the shaking of his beard, may peace be upon him. Translation Not Available

Book Ref: Sunan Abi Dawud Book 2 Hadith 801
Web Ref:  Sunan Abi Dawud Book 2 Hadith 800