To lie flat (on the back) in the mosque

Narrated 'Abbad bin Tamim:

that his uncle said, "I saw Allah's Apostle lying flat (on his back) in the mosque with one leg on the other." Narrated Said bin Al-Musaiyab that 'Umar and 'Uthman used to do the same.

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عَبَّادِ بْنِ تَمِيمٍ، عَنْ عَمِّهِ، أَنَّهُ رَأَى رَسُولَ اللَّهِ ﷺ مُسْتَلْقِيًا فِي الْمَسْجِدِ، وَاضِعًا إِحْدَى رِجْلَيْهِ عَلَى الأُخْرَى. وَعَنِ ابْنِ شِهَابٍ عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ قَالَ كَانَ عُمَرُ وَعُثْمَانُ يَفْعَلاَنِ ذَلِكَ.