Hadithcore
Mishkat al-Masabih, 4056

‘Umar said that the properties of the B. an-Nadir were part of what God bestowed on His Messenger from what the Muslims had not ridden on horses or camels to get; so they belonged specially to God’s Messenger who gave his family their annual contribution, then applied what remained for weapons and horses as equipment in God’s path. (Bukhari and Muslim.)

وَعَن عمر قَالَ: كَانَتْ أَمْوَالُ بَنِي النَّضِيرِ مِمَّا أَفَاءَ اللَّهُ عَلَى رَسُولِهِ مِمَّا لَمْ يُوجِفِ الْمُسْلِمُونَ عَلَيْهِ بِخَيْلٍ وَلَا رِكَابٍ فَكَانَتْ لِرَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ خَالِصَة يُنْفِقُ عَلَى أَهْلِهِ نَفَقَةَ سَنَتِهِمْ ثُمَّ يَجْعَلُ مَا بَقِيَ فِي السِّلَاحِ وَالْكُرَاعِ عُدَّةً فِي سَبِيل الله

References1 variant
In-Book Reference
Book 19, Hadith 266