Muwatta Malik #297

Yahya related to me from Malik from Zayd ibn Aslam from a man of the Bani'd-Dil called Busr ibn Mihjan from his father Mihjan that he was in a gathering with the Messenger of Allah, may Allah bless him and grant him peace, and the call to prayer was made. The Messenger of Allah, may Allah bless him and grant him peace, rose and prayed and then returned. Mihjan remained sitting and did not pray with him. The Messenger of Allah, may Allah bless him and grant him peace, said, "What prevented you from praying with the people? Aren't you a muslim?" He said, "Of course, Messenger of Allah, but I have already prayed with my family." The Messenger of Allah, may Allah bless him and grant him peace, said, "When you come, pray with the people, even if you have prayed already."