حَدَّثَنَا وَكِيعٌ عَنْ سُفْيَانَ عَنْ فِرَاسٍ عَنْ أَبِي صَالِحٍ عَنْ زَاذَانَ أَنَّ ابْنَ عُمَرَ أَعْتَقَ عَبْدًا لَهُ فَقَالَ مَا لِي مِنْ أَجْرِهِ وَتَنَاوَلَ شَيْئًا مِنْ الْأَرْضِ مَا يَزِنُ هَذِهِ أَوْ مِثْلَ هَذِهِ سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ مَنْ لَطَمَ غُلَامَهُ أَوْ ضَرَبَهُ فَكَفَّارَتُهُ عِتْقُهُ
مسند امام احمد بن حنبل · Hadith 5266
It was narrated from Zadhaan that Ibn 'Umar manumitted a slave of his and said: I am not going to get reward (for manumitting him) - and he picked up something from the ground - even as much as this - or like this. I heard the Messenger of Allah (PBUH) say: "Whoever slaps his slave or beats him, his expiation is to manumit him."
Sanad
حَدَّثَنَا وَكِيعٌ عَنْ سُفْيَانَ عَنْ فِرَاسٍ عَنْ أَبِي صَالِحٍ عَنْ زَاذَانَ