It was narrated that Aisha(ra) said:"The messenger of Allah(ﷺ) was asked during the campaign of Tabuk about the Sutra of one who is praying. He said: "Something as high as the back of a camel saddle."
أَخْبَرَنَا الْعَبَّاسُ بْنُ مُحَمَّدٍ الدُّورِيُّ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يَزِيدَ، قَالَ حَدَّثَنَا حَيْوَةُ بْنُ شُرَيْحٍ، عَنْ أَبِي الأَسْوَدِ، عَنْ عُرْوَةَ، عَنْ عَائِشَةَ، - رضى الله عنها - قَالَتْ سُئِلَ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي غَزْوَةِ تَبُوكَ عَنْ سُتْرَةِ الْمُصَلِّي فَقَالَ " مِثْلُ مُؤْخِرَةِ الرَّحْلِ " .
Nesai
The Book of the Qiblah • Hadith 746