حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ أَبِي الزِّنَادِ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّهُ قَالَ كَانَ النَّاسُ يُعْطَوْنَ النَّفَلَ مِنَ الْخُمُسِ ‏.‏ قَالَ مَالِكٌ وَذَلِكَ أَحْسَنُ مَا سَمِعْتُ إِلَىَّ فِي ذَلِكَ ‏.‏ وَسُئِلَ مَالِكٌ عَنِ النَّفَلِ هَلْ يَكُونُ فِي أَوَّلِ مَغْنَمٍ قَالَ ذَلِكَ عَلَى وَجْهِ الاِجْتِهَادِ مِنَ الإِمَامِ وَلَيْسَ عِنْدَنَا فِي ذَلِكَ أَمْرٌ مَعْرُوفٌ مَوْثُوقٌ إِلاَّ اجْتِهَادُ السُّلْطَانِ وَلَمْ يَبْلُغْنِي أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَفَّلَ فِي مَغَازِيهِ كُلِّهَا وَقَدْ بَلَغَنِي أَنَّهُ نَفَّلَ فِي بَعْضِهَا يَوْمَ حُنَيْنٍ وَإِنَّمَا ذَلِكَ عَلَى وَجْهِ الاِجْتِهَادِ مِنَ الإِمَامِ فِي أَوَّلِ مَغْنَمٍ وَفِيمَا بَعْدَهُ ‏.‏

Yahya related to me from Malik from Abu'z-Zinad that Said ibn al-Musayyab said, "People used to be given bonuses from the Khumus." Malik said, "That is the best of what I have heard on the matter." Malik was asked about bonuses and whether they were takenfrom the first of the spoils, and he said, "That is only decidedaccording to the ijtihad of the Imam. We do not have a known reliablecommand about that other than it is up to the ijtihad of the Sultan. Ihave not heard that the Messenger of Allah, may Allah bless him andgrant him peace, gave bonuses in all his raids. I have only heard thathe gave bonuses in one of them, namely the day of Hunayn. It dependson the ijtihad of the Imam whether they are taken from the first ofthe spoils or what is after it." Translation Not Available

Book reference: Muwatta Imam Malik Book 21 Hadith 981
Web reference: Muwatta Imam Malik Book 21 Hadith 20