(Explanation of praying with the congregation after the obligatory prayer)

Yazid b. al-Aswad said:I was present with the Prophet at his pilgrimage and prayed the Morning Prayer along with him in the mosque of al-Khaif. When he finished his prayer and turned away there were two men at the back of the people who had not prayed along with him. He said, “Bring them to me,” and they were brought trembling with fear. He asked what had prevented them from praying along with him, and they replied, “Messenger of God, we had already prayed in our lodging.” He said, “Don’t do so. When you pray in your lodging and then come to a mosque where there is a congregation, you must pray along with them, and it will be a supererogatory prayer for you. Tirmidhi, Abu Dawud and Nasa’i transmitted it.