The wealth of Banu Nadir was among what Allah bestowed upon His Messenger as spoils which the Muslims had not driven any horses or camels to obtain. It belonged exclusively to the Messenger of Allah ﷺ. The Messenger of Allah ﷺ would set aside from it a year's provision for his family, then allocate what remained for horses and weapons as preparation for the cause of Allah.
حدثنا ابن أبي عمر حدثنا سفيان بن عيينة عن عمرو بن دينار عن ابن شهاب عن مالك بن أوس بن الحدثان قال سمعت
كانت أموال بني النضير مما أفاء الله على رسوله مما لم يوجف المسلمون عليه بخيل ولا ركاب وكانت لرسول الله ﷺ خالصا وكان رسول الله ﷺ يعزل نفقة أهله سنة ثم يجعل ما بقي في الكراع والسلاح عدة في سبيل الله
Graded as agreed upon [by Bukhari and Muslim]. Bukhari transmitted it in the Book of Jihad and Expeditions, chapter on the shield and one who shields himself with his companion's shield, hadith no. 2904, and Muslim, hadith no. 1757, both from the hadith of Sufyan bin Uyayna, through this same chain.