Jami` at-Tirmidhi 3079
Narrated Mus'ab bin Sa'd:
from his father who said: "On the Day of Badr I brought a sword so I said: 'O Messenger of Allah! Indeed Allah has satisfied my breast (i.e. my desire) on the idolaters - or something like that - give me this sword.' So he said: 'This is not for me, nor is it for you.' I said: 'Perhaps he will give this to someone who did not go through some struggle I went through (fighting).' So the Messenger of Allah (ﷺ) came to me [and he said:] 'You asked me, but it was not up to me. But now it has occurred that it is up to me, so it is yours.'" He said: "So (the following) was revealed: They ask you about the spoils of war (8:1)."
حَدَّثَنَا أَبُو كُرَيْبٍ، حَدَّثَنَا أَبُو بَكْرِ بْنُ عَيَّاشٍ، عَنْ عَاصِمِ بْنِ بَهْدَلَةَ، عَنْ مُصْعَبِ بْنِ سَعْدٍ، عَنْ أَبِيهِ، قَالَ لَمَّا كَانَ يَوْمُ بَدْرٍ جِئْتُ بِسَيْفٍ فَقُلْتُ يَا رَسُولَ اللَّهِ إِنَّ اللَّهَ قَدْ شَفَى صَدْرِي مِنَ الْمُشْرِكِينَ أَوْ نَحْوَ هَذَا هَبْ لِي هَذَا السَّيْفَ ‏.‏ فَقَالَ ‏"‏ هَذَا لَيْسَ لِي وَلاَ لَكَ ‏"‏ ‏.‏ فَقُلْتُ عَسَى أَنْ يُعْطَى هَذَا مَنْ لاَ يُبْلِي بَلاَئِي فَجَاءَنِي الرَّسُولُ فَقَالَ ‏"‏ إِنَّكَ سَأَلْتَنِي وَلَيْسَ لِي وَقَدْ صَارَ لِي وَهُوَ لَكَ ‏"‏ ‏.‏ قَالَ فَنَزَلَتْ ‏:‏ ‏(‏ يَسْأَلُونَكَ عَنِ الأَنْفَالِ ‏)‏ الآيَةَ ‏.‏ قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ ‏.‏ وَقَدْ رَوَاهُ سِمَاكُ بْنُ حَرْبٍ عَنْ مُصْعَبِ بْنِ سَعْدٍ أَيْضًا ‏.‏ وَفِي الْبَابِ عَنْ عُبَادَةَ بْنِ الصَّامِتِ ‏.‏