The Prophet (may Allah's peace and blessings be upon him) forbade Hibwah (a sitting position) on Friday while the Imām is delivering the sermon
Mu‘ādh ibn Anas al-Juhani (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) forbade Hibwah (a sitting position) on Friday while the Imām is delivering the sermon.

