أَبُو أَبِي الْخَرِيفِ

[Machine] I came with my brother, the Messenger of Allah ﷺ , while he was praying in the Masjid al-Khaif, and we had already prayed the obligatory prayers at home, so we did not pray with them. He said, "What prevented you both from praying with us?" We said, "We have already prayed the obligatory prayers at home." So the Messenger of Allah ﷺ said, "When a man prays the obligatory prayers at home and then joins a congregation, his prayer in his house becomes a voluntary prayer."  

أَتَيْتُ أَنَا وَأَخِي رَسُولَ اللهِ ﷺ وَهُوَ فِي مَسْجِدِ الْخَيْفِ يُصَلِّي وَقَدْ صَلَّيْنَا الْمَكْتُوبَةَ فِي الْبَيْتِ فَلَمْ نُصَلِّ مَعَهُمْ فَقَالَ «مَا مَنَعَكُمَا أَنْ تُصَلِّيَا مَعَنَا؟» قُلْنَا قَدْ كُنَّا صَلَّيْنَا الْمَكْتُوبَةَ فِي الْبَيْتِ فَقَالَ رَسُولُ اللهِ ﷺ «إِذَا صَلَّى الرَّجُلُ الْمَكْتُوبَةَ فِي الْبَيْتِ ثُمَّ أَدْرَكَ جَمَاعَةً فَلْيُصَلِّ مَعَهُمْ فَتَكُونُ صَلَاتُهُ فِي بَيْتِهِ نَافِلَةً»