Sahih Bukhari Volume 4, Book 56, Hadith 2980

حَدَّثَنَا عُبَيْدُ بْنُ إِسْمَاعِيلَ، حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ هِشَامٍ، قَالَ أَخْبَرَنِي أَبِي وَ، حَدَّثَتْنِي أَيْضًا، فَاطِمَةُ عَنْ أَسْمَاءَ ـ رضى الله عنها ـ قَالَتْ صَنَعْتُ سُفْرَةَ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي بَيْتِ أَبِي بَكْرٍ حِينَ أَرَادَ أَنْ يُهَاجِرَ إِلَى الْمَدِينَةِ، قَالَتْ فَلَمْ نَجِدْ لِسُفْرَتِهِ وَلاَ لِسِقَائِهِ مَا نَرْبِطُهُمَا بِهِ، فَقُلْتُ لأَبِي بَكْرٍ وَاللَّهِ مَا أَجِدُ شَيْئًا أَرْبِطُ بِهِ إِلاَّ نِطَاقِي‏.‏ قَالَ فَشُقِّيهِ بِاثْنَيْنِ، فَارْبِطِيهِ بِوَاحِدٍ السِّقَاءَ وَبِالآخَرِ السُّفْرَةَ‏.‏ فَفَعَلْتُ، فَلِذَلِكَ سُمِّيَتْ ذَاتَ النِّطَاقَيْنِ‏

Narrated By Asma : I prepared the journey-food for Allah's Apostle in Abu Bakr's house when he intended to emigrate to Medina. I could not find anything to tie the food-container and the water skin with. So, I said to Abu Bakr, "By Allah, I do not find anything to tie (these things) with except my waist belt." He said, "Cut it into two pieces and tie the water-skin with one piece and the food-container with the other (the sub-narrator added, "She did accordingly and that was the reason for calling her Dhatun-Nitaqain (i.e. two-belted woman))."