Language:
كتاب السلم
35  
Sales in which a Price is paid for Goods to be Delivered Later (As-Salam)
(6)
Chapter: Mortgaging in As-Salam
(6)
باب الرَّهْنِ فِي السَّلَمِ
Sahih al-Bukhari 2252

Narrated Al-A`mash:

We argued at Ibrahim's dwelling place about mortgaging in Salam. He said, "Aisha said, 'The Prophet (ﷺ) bought some foodstuff from a Jew on credit and the payment was to be made by a definite period, and he mortgaged his iron armor to him."

حَدَّثَنِي مُحَمَّدُ بْنُ مَحْبُوبٍ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، حَدَّثَنَا الأَعْمَشُ، قَالَ تَذَاكَرْنَا عِنْدَ إِبْرَاهِيمَ الرَّهْنَ فِي السَّلَفِ فَقَالَ حَدَّثَنِي الأَسْوَدُ عَنْ عَائِشَةَ ـ رضى الله عنها ـ أَنَّ النَّبِيَّ صلى الله عليه وسلم اشْتَرَى مِنْ يَهُودِيٍّ طَعَامًا إِلَى أَجَلٍ مَعْلُومٍ، وَارْتَهَنَ مِنْهُ دِرْعًا مِنْ حَدِيدٍ‏.‏
Reference : Sahih al-Bukhari 2252
In-book reference : Book 35, Hadith 13
USC-MSA web (English) reference : Vol. 3, Book 35, Hadith 454
  (deprecated numbering scheme)