The mortgaging in places occupied by settled population and the Statement of Allah تعالى: "And if you are on a journey and cannot find a scribe, then let there be a pledge taken (i.e., mortgaging)..." (V.2:283)
Narrated Anas:
No doubt, the Prophet (ﷺ) mortgaged his armor for barley grams. Once I took barley bread with some dissolved fat on it to the Prophet (ﷺ) and I heard him saying, "The household of Muhammad did not possess except a Sa (of food grain, barley, etc.) for both the morning and the evening meals although they were nine houses."
حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ حَدَّثَنَا هِشَامٌ حَدَّثَنَا قَتَادَةُ عَنْ أَنَسٍ ـ رضى الله عنه ـ قَالَ وَلَقَدْ رَهَنَ النَّبِيُّ صلى الله عليه وسلم دِرْعَهُ بِشَعِيرٍ وَمَشَيْتُ إِلَى النَّبِيِّ صلى الله عليه وسلم بِخُبْزِ شَعِيرٍ وَإِهَالَةٍ سَنِخَةٍ وَلَقَدْ سَمِعْتُهُ يَقُولُ مَا أَصْبَحَ لآلِ مُحَمَّدٍ صلى الله عليه وسلم إِلاَّ صَاعٌ وَلاَ أَمْسَى وَإِنَّهُمْ لَتِسْعَةُ أَبْيَاتٍ