Musannaf Ibn Abi Shayba 35:129

Hushaym narrated to us, Ya'la ibn 'Ata' informed us, he said: Jabir ibn al-Aswad narrated to me, from his father, who said: I witnessed the Hajj with the Prophet, may Allah bless him and grant him peace. He said: I prayed the morning prayer with him in the Mosque of al-Khayf. When he finished his prayer and turned, he saw two men at the back of the people who had not prayed with him. He said: "Bring them to me." They were brought to him, their shoulders trembling. He said: "What prevented you from praying with us?" They said: "O Messenger of Allah, we had already prayed in our dwellings." He said: "Do not do that. If you have prayed in your dwellings and then come to a congregational mosque, pray with them, for it is a supererogatory prayer for you."