"I participated at Khaibar with my masters. They spoke about me to the Messenger of Allah (ﷺ) and told him that I was a slave." He said: "So he ordered me to take up the sword, and I found myself dragging it, so he ordered that I be given something from the goods. I presented a Ruqyah that I used to treat the possessed with, so he ordered me leave some of it and keep some of it." There is something on this topic from Ibn 'Abbas. This Hadith is Hasan Sahih. This is acted upon according to the some of the people of knowledge. A complete portion is not given to slave, but something is conferred upon him. This is the view of Ath-Thawri, Ash-Shafi'i, Ahmad, and Ishaq.
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا بِشْرُ بْنُ الْمُفَضَّلِ، عَنْ مُحَمَّدِ بْنِ زَيْدٍ، عَنْ عُمَيْرٍ، مَوْلَى آبِي اللَّحْمِ قَالَ شَهِدْتُ خَيْبَرَ مَعَ سَادَتِي فَكَلَّمُوا فِيَّ رَسُولَ اللَّهِ صلى الله عليه وسلم وَأَعْلَمُوهُ أَنِّي مَمْلُوكٌ . قَالَ فَأَمَرَ بِي فَقُلِّدْتُ السَّيْفَ فَإِذَا أَنَا أَجُرُّهُ فَأَمَرَ لِي بِشَيْءٍ مِنْ خُرْثِيِّ الْمَتَاعِ وَعَرَضْتُ عَلَيْهِ رُقْيَةً كُنْتُ أَرْقِي بِهَا الْمَجَانِينَ فَأَمَرَنِي بِطَرْحِ بَعْضِهَا وَحَبْسِ بَعْضِهَا . وَفِي الْبَابِ عَنِ ابْنِ عَبَّاسٍ . وَهَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ . وَالْعَمَلُ عَلَى هَذَا عِنْدَ بَعْضِ أَهْلِ الْعِلْمِ أَنْ لاَ يُسْهَمَ لِلْمَمْلُوكِ وَلَكِنْ يُرْضَخُ لَهُ بِشَيْءٍ . وَهُوَ قَوْلُ الثَّوْرِيِّ وَالشَّافِعِيِّ وَأَحْمَدَ وَإِسْحَاقَ .
Tirmizi
The Book on Military Expeditions • Hadith 1594