"It has not reached me that the Messenger of Allah ﷺ gave the Nafl during every expedition, but it has been conveyed to me that he gave the Nafl in some of them. That is according to the discretion of the Imam during the beginning of the division of the spoils or the end of it." Ibn Mansur said: "I said to Ahmad: 'The Prophet ﷺ gave the Nafl when he divided the fourth, after the Khumus, and when he was returning (he gave) the third from the Khumus.' So he said: 'The Khumus is taken, and then the Nafl is given from what remains, nothing beyond this.''"
أَنَّ النَّبِيَّ ﷺ تَنَفَّلَ سَيْفَهُ ذَا الْفَقَارِ يَوْمَ بَدْرٍ وَهُوَ الَّذِي رَأَى فِيهِ الرُّؤْيَا يَوْمَ أُحُدٍ هَذَا حَدِيثٌ حَسَنٌ غَرِيبٌ إِنَّمَا نَعْرِفُهُ مِنْ هَذَا الْوَجْهِ مِنْ حَدِيثِ ابْنِ أَبِي الزِّنَادِ وَقَدِ اخْتَلَفَ أَهْلُ الْعِلْمِ فِي النَّفَلِ مِنَ الْخُمُسِ فَقَالَ مَالِكُ بْنُ أَنَسٍ لَمْ يَبْلُغْنِي أَنَّ رَسُولَ اللَّهِ ﷺ نَفَّلَ فِي مَغَازِيهِ كُلِّهَا وَقَدْ بَلَغَنِي أَنَّهُ نَفَّلَ فِي بَعْضِهَا وَإِنَّمَا ذَلِكَ عَلَى وَجْهِ الاِجْتِهَادِ مِنَ الإِمَامِ فِي أَوَّلِ الْمَغْنَمِ وَآخِرِهِ قَالَ ابْنُ مَنْصُورٍ قُلْتُ لأَحْمَدَ إِنَّ النَّبِيَّ ﷺ نَفَّلَ إِذَا فَصَلَ بِالرُّبُعِ بَعْدَ الْخُمُسِ وَإِذَا قَفَلَ بِالثُّلُثِ بَعْدَ الْخُمُسِ فَقَالَ يُخْرِجُ الْخُمُسَ ثُمَّ يُنَفِّلُ مِمَّا بَقِيَ وَلاَ يُجَاوِزُ هَذَا