"The Messenger of Allah ﷺ used to accept the invitation of a slave."  

سَمِعَ أَنَسَ بْنَ مَالِكٍ يَقُولُ كَانَ رَسُولُ اللَّهِ ﷺ يُجِيبُ دَعْوَةَ الْمَمْلُوكِ  

"My master used to give me food and I would feed others from it, then he stopped me," or he said: "He beat me. So I asked the Prophet,” -or- "he asked him and I said: 'I will not stop.' He said: 'Both of you will be rewarded."'  

كَانَ مَوْلاَىَ يُعْطِينِي الشَّىْءَ فَأُطْعِمُ مِنْهُ فَمَنَعَنِي أَوْ قَالَ فَضَرَبَنِي فَسَأَلْتُ النَّبِيَّ ﷺ أَوْ سَأَلَهُ فَقُلْتُ لاَ أَنْتَهِي أَوْ لاَ أَدَعُهُ فَقَالَ الأَجْرُ بَيْنَكُمَا