Muwatta Malik, Book 9, Hadith 421 (In-Book)

Yahya related to me from Malik from Ibn Shihab from Abbad ibn Tamim from his paternal uncle that he saw the Messenger of Allah, may Allah bless him and grant him peace, lying down in the mosque with one foot on top of the other.

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عَبَّادِ بْنِ تَمِيمٍ، عَنْ عَمِّهِ، أَنَّهُ رَأَى رَسُولَ اللَّهِ صلى الله عليه وسلم مُسْتَلْقِيًا فِي الْمَسْجِدِ وَاضِعًا إِحْدَى رِجْلَيْهِ عَلَى الأُخْرَى ‏.‏

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also referenced under: Book 9, Hadith 90 (USC-MSA)