From Sahih Bukhari (Hadith 3907):
Narrated Asma:I prepared the journey food for the Prophet (ﷺ) and Abu Bakr when they wanted (to migrate to) Medina. I said to my father (Abu Bakr), "I do not have anything to tie the container of the journey food with except my waist belt." He said, "Divide it lengthwise into two." I did so, and for this reason I was named 'Dhat-un-Nitaqain' (i.e. the owner of two belts). (Ibn `Abbas said, "Asma', Dhat-un-Nitaq)
Reference: Bukhari 3907