Language:
كتاب الصلاة
8  
Prayers (Salat)
(3)
Chapter: To tie Izar (dress worn below the waist) at one's back while offering Salat (prayers)
(3)
باب عَقْدِ الإِزَارِ عَلَى الْقَفَا فِي الصَّلاَةِ
Sahih al-Bukhari 352

Narrated Muhammad bin Al-Munkadir:

Once Jabir prayed with his Izar tied to his back while his clothes were Lying beside him on a wooden peg. Somebody asked him, "Do you offer your prayer in a single Izar?" He replied, "I did so to show it to a fool like you. Had anyone of us two garments in the lifetime of the Prophet?"

حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ، قَالَ حَدَّثَنَا عَاصِمُ بْنُ مُحَمَّدٍ، قَالَ حَدَّثَنِي وَاقِدُ بْنُ مُحَمَّدٍ، عَنْ مُحَمَّدِ بْنِ الْمُنْكَدِرِ، قَالَ صَلَّى جَابِرٌ فِي إِزَارٍ قَدْ عَقَدَهُ مِنْ قِبَلِ قَفَاهُ، وَثِيَابُهُ مَوْضُوعَةٌ عَلَى الْمِشْجَبِ قَالَ لَهُ قَائِلٌ تُصَلِّي فِي إِزَارٍ وَاحِدٍ فَقَالَ إِنَّمَا صَنَعْتُ ذَلِكَ لِيَرَانِي أَحْمَقُ مِثْلُكَ، وَأَيُّنَا كَانَ لَهُ ثَوْبَانِ عَلَى عَهْدِ النَّبِيِّ صلى الله عليه وسلم
Reference : Sahih al-Bukhari 352
In-book reference : Book 8, Hadith 4
USC-MSA web (English) reference : Vol. 1, Book 8, Hadith 348
  (deprecated numbering scheme)