Musnad Ahmad 487:1

Hashim narrated to us, Ya’la ibn ‘Ata’ narrated to us, he said: Jabir ibn Yazid ibn al-Aswad al-‘Amiri narrated to me, from his father, he said: I witnessed the Hajj with the Messenger of Allah, may Allah bless him and grant him peace. He said: So I prayed the dawn prayer with him in the Mosque of al-Khayf. When he finished his prayer, behold, there were two men at the back of the mosque who did not pray with him. He said: "Bring them to me." So they were brought, 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, then you come to a congregational mosque, pray with them, for it will be a supererogatory prayer for you." And it was sometimes said to Hashim: "When he finished his prayer," he would correct it and say: "He turned from his place."