Mukhtasar Bukhari (Abridged) 431 — Looking at the imam during prayer

It was asked from Sayyiduna Khabbab (may Allah be pleased with him) whether the Messenger of Allah (peace and blessings be upon him) used to recite (something) in the Zuhr and Asr prayers? Khabbab (may Allah be pleased with him) said: Yes. It was asked: By what did you distinguish this? So Khabbab (may Allah be pleased with him) replied: By the movement of the blessed beard of the Messenger of Allah (peace and blessings be upon him).