Narrated Umar:

The properties of Bam An-Nadir were among the booty that Allah gave to His Apostle such Booty were not obtained by any expedition on the part of Muslims, neither with cavalry, nor with camelry. So those properties were for Allah's Apostle only, and he used to provide thereof the yearly expenditure for his wives, and dedicate the rest of its revenues for purchasing arms and horses as war material to be used in Allah's Cause.

حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا سُفْيَان ُ ـ غَيْرَ مَرَّةٍ ـ عَنْ عَمْرٍو، عَنِ الزُّهْرِيِّ، عَنْ مَالِكِ بْنِ أَوْسِ بْنِ الْحَدَثَانِ، عَنْ عُمَرَ ـ رضى الله عنه ـ قَالَ كَانَتْ أَمْوَالُ بَنِي النَّضِيرِ مِمَّا أَفَاءَ اللَّهُ عَلَى رَسُولِهِ ﷺ مِمَّا لَمْ يُوجِفِ الْمُسْلِمُونَ عَلَيْهِ بِخَيْلٍ وَلاَ رِكَابٍ، فَكَانَتْ لِرَسُولِ اللَّهِ ﷺ خَاصَّةً، يُنْفِقُ عَلَى أَهْلِهِ مِنْهَا نَفَقَةَ سَنَتِهِ، ثُمَّ يَجْعَلُ مَا بَقِيَ فِي السِّلاَحِ وَالْكُرَاعِ، عُدَّةً فِي سَبِيلِ اللَّهِ.