Sahih Muslim , Book 5, Hadith 2236 (USC-MSA) ⓘ
Umair, the freed slave of Abi'l-Lahm reported: I was the slave (of Abi'l-Lahm). I asked the Messenger of Allah if I could give some charity out of my master's wealth. He said: Yes, and the reward is half and half between you two.
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَابْنُ، نُمَيْرٍ وَزُهَيْرُ بْنُ حَرْبٍ جَمِيعًا عَنْ حَفْصِ، بْنِ غِيَاثٍ - قَالَ ابْنُ نُمَيْرٍ حَدَّثَنَا حَفْصٌ، - عَنْ مُحَمَّدِ بْنِ زَيْدٍ، عَنْ عُمَيْرٍ، مَوْلَى آبِي اللَّحْمِ قَالَ كُنْتُ مَمْلُوكًا فَسَأَلْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم أَأَتَصَدَّقُ مِنْ مَالِ مَوَالِيَّ بِشَىْءٍ قَالَ " نَعَمْ وَالأَجْرُ بَيْنَكُمَا نِصْفَانِ " .
also referenced under: Book 12, Hadith 105 (In-Book) & Hadith 1025 (Reference)