We asked Khabbab whether Messenger of Allah ﷺ used to recite (the Qur'an) in the Zuhr and the ʿAsr prayers. He replied in the affirmative. We said, "How did you come to know about it?" He said, "By the movement of his beard."
قُلْنَا لِخَبَّابٍ أَكَانَ رَسُولُ اللَّهِ ﷺ يَقْرَأُ فِي الظُّهْرِ وَالْعَصْرِ قَالَ نَعَمْ قُلْنَا بِمَ كُنْتُمْ تَعْرِفُونَ ذَاكَ قَالَ بِاضْطِرَابِ لِحْيَتِهِ