It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the people were performing the morning prayer in the mosque of Quba when a man came and said, "Last night, Qur'an was revealed to the Noble Prophet (peace and blessings be upon him), in which he was commanded to face the Ka'bah during prayer." Upon hearing this, those people turned towards the Ka'bah during the prayer itself.