‘Umar sent for me... and he mentioned a similar hadeeth. He said: The wealth of Banun-Nadeer was among the faiʿ that Allah granted to His Messenger for which the Muslims made no expedition with either cavalry or camelry (cf. al-Hashr 59:6). He allocated some of it for his familyʿs maintenance for one year, and what was left he spent on horses and weapons in preparation for jihad for the sake of Allah, may He be glorified and exalted.
وَقَالَ إِنَّ أَمْوَالَ بَنِي النَّضِيرِ كَانَتْ مِمَّا أَفَاءَ اللهُ عَلَى رَسُولِهِ مِمَّا لَمْ يُوجِفْ عَلَيْهِ الْمُسْلِمُونَ بِخَيْلٍ وَلارِكَابٍ فَكَانَ يُنْفِقُ عَلَى أَهْلِهِ مِنْهَا نَفَقَةَ سَنَتِهِ وَمَا بَقِيَ جَعَلَهُ فِي الْكُرَاعِ وَالسِّلَاحِ عُدَّةً فِي سَبِيلِ اللهِ ﷻ