Musnad Ahmad 281
It was narrated that ‘Umar bin al-Khattab said:
I gave a horse for the sake of Allah, but its owner neglected it. I thought that he would sell it for a cheap price, but I said to myself, not until I ask the Messenger of Allah (ﷺ) about that. He said: “Do not buy it even if he gives it to you for a dirham, for the one who takes back his charity is like the dog that goes back to its vomit.”
حَدَّثَنَا عَبْدُ الرَّحْمَنِ، عَنْ مَالِكٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ أَبِيهِ، عَنْ عُمَرَ بْنِ الْخَطَّابِ، رَضِيَ اللَّهُ عَنْهُ قَالَ حَمَلْتُ عَلَى فَرَسٍ فِي سَبِيلِ اللَّهِ فَأَضَاعَهُ صَاحِبُهُ فَأَرَدْتُ أَنْ أَبْتَاعَهُ وَظَنَنْتُ أَنَّهُ بَائِعُهُ بِرُخْصٍ فَقُلْتُ حَتَّى أَسْأَلَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ لَا تَبْتَعْهُ وَإِنْ أَعْطَاكَهُ بِدِرْهَمٍ فَإِنَّ الَّذِي يَعُودُ فِي صَدَقَتِهِ فَكَالْكَلْبِ يَعُودُ فِي قَيْئِهِ‏.‏