Sahih al-Bukhari 777
Book 10: Call to Prayers (Adhaan) · Narrated by Abu Ma`mar
Arabic
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، عَنْ عُمَارَةَ بْنِ عُمَيْرٍ، عَنْ أَبِي مَعْمَرٍ، قُلْتُ لِخَبَّابٍ أَكَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَقْرَأُ فِي الظُّهْرِ وَالْعَصْرِ قَالَ نَعَمْ. قُلْنَا مِنْ أَيْنَ عَلِمْتَ قَالَ بِاضْطِرَابِ لِحْيَتِهِ.
English translation
Narrated Abu Ma`mar:We said to Khabbab "Did Allah's Messenger (ﷺ) used to recite in Zuhr and `Asr prayers?" He replied in the affirmative. We said, "How did you come to know about it?" He said, "By the movement of his beard
Reference: Sahih al-Bukhari 777, Book of Call to Prayers (Adhaan). English translation by Dr. Muhammad Muhsin Khan.