حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَابْنُ، نُمَيْرٍ قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ بِشْرٍ، حَدَّثَنَا عُبَيْدُ اللَّهِ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَرْكُزُ - وَقَالَ أَبُو بَكْرٍ يَغْرِزُ - الْعَنَزَةَ وَيُصَلِّي إِلَيْهَا ‏.‏ زَادَ ابْنُ أَبِي شَيْبَةَ قَالَ عُبَيْدُ اللَّهِ وَهْىَ الْحَرْبَةُ ‏.‏

Ibn Umar reported: The Apostle of Allah (PBUH) set up (sutra), and Abu Bakr said: He implanted iron-tipped spear and said prayer towards its direction. Ibn Abu Shaiba made this addition to it:" Ubaidullah said that it was a spear." Translation Not Available

Book Ref: Sahih Muslim Book 4 Hadith 1011
Web Ref:  Sahih Muslim Book 4 Hadith 501 b