Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
bayhaqi:7633[Chain 1] Abū al-Ḥasan ʿAlī b. Aḥmad b. ʿAbdān > Aḥmad b. ʿUbayd al-Ṣaffār > Ismāʿīl b. Isḥāq al-Qāḍī And ʾIbrāhīm b. ʿAbdullāh > al-Qaʿnabī [Chain 2] Abū ʿAbdullāh al-Ḥāfiẓ > Abū al-Ḥasan Aḥmad b. Muḥammad b. ʿAbdūs > ʿUthmān b. Saʿīd al-Dārimī > al-Qaʿnabī Fīmā Qaraʾ > Mālik > Zayd b. Aslam from his father > ʿUmar b. al-Khaṭṭāb ؓ

[Machine] "Regarding this, the Messenger of Allah ﷺ said, 'Do not buy it, even if he gives it to you for one dirham, for the return on his charity is like a dog that returns to its vomit.'"  

البيهقي:٧٦٣٣أَخْبَرَنَا أَبُو الْحَسَنِ عَلِيُّ بْنُ أَحْمَدَ بْنِ عَبْدَانَ أنبأ أَحْمَدُ بْنُ عُبَيْدٍ الصَّفَّارُ ثنا إِسْمَاعِيلُ بْنُ إِسْحَاقَ الْقَاضِي وَإِبْرَاهِيمُ بْنُ عَبْدِ اللهِ قَالَا ثنا الْقَعْنَبِيُّ ح وَأَخْبَرَنَا أَبُو عَبْدِ اللهِ الْحَافِظُ وَاللَّفْظُ لَهُ قَالَ أَخْبَرَنِي أَبُو الْحَسَنِ أَحْمَدُ بْنُ مُحَمَّدِ بْنِ عَبْدُوسٍ ثنا عُثْمَانُ بْنُ سَعِيدٍ الدَّارِمِيُّ ثنا الْقَعْنَبِيُّ فِيمَا قَرَأَ عَلَى مَالِكٍ عَنْ زَيْدِ بْنِ أَسْلَمَ عَنْ أَبِيهِ أَنَّهُ قَالَ سَمِعْتُ عُمَرَ بْنَ الْخَطَّابِ ؓ يَقُولُ حَمَلْتُ عَلَى فَرَسٍ عَتِيقٍ فِي سَبِيلِ اللهِ فَأَضَاعَهُ صَاحِبُهُ الَّذِي كَانَ عِنْدَهُ فَأَرَدْتُ أَنْ أَشْتَرِيَهُ مِنْهُ وَظَنَنْتُ أَنَّهُ بَائِعُهُ بِرُخْصٍ فَسَأَلْتُ

عَنْ ذَلِكَ رَسُولَ اللهِ ﷺ فَقَالَ لَا تَشْتَرِهِ وَإِنْ أَعْطَاكَ بِدِرْهَمٍ وَاحِدٍ فَإِنَّ الْعَائِدَ فِي صَدَقَتِهِ كَالْكَلْبِ يَعُودُ فِي قَيْئِهِ  

رَوَاهُ مُسْلِمٌ فِي الصَّحِيحِ عَنِ الْقَعْنَبِيِّ وَأَخْرَجَهُ الْبُخَارِيِّ عَنْ جَمَاعَةٍ عَنْ مَالِكٍ

See similar narrations below:

Collected by Bukhārī, Ibn Ḥibbān
bukhari:2623Yaḥyá b. Qazaʿah > Mālik > Zayd b. Aslam from his father > ʿUmar b. al-Khaṭṭāb

I gave a horse in Allah's Cause. The person to whom it was given, did not look after it. I intended to buy it from him, thinking that he would sell it cheap. When I asked the Prophet ﷺ he said, "Don't buy it, even if he gives it to you for one Dirham, as the person who takes back what he has given in charity, is like a dog that swallows back its vomit."  

البخاري:٢٦٢٣حَدَّثَنَا يَحْيَى بْنُ قَزَعَةَ حَدَّثَنَا مَالِكٌ عَنْ زَيْدِ بْنِ أَسْلَمَ عَنْ أَبِيهِ سَمِعْتُ عُمَرَ بْنَ الْخَطَّابِ ؓ يَقُولُ حَمَلْتُ عَلَى فَرَسٍ فِي سَبِيلِ اللَّهِ فَأَضَاعَهُ الَّذِي كَانَ عِنْدَهُ فَأَرَدْتُ أَنْ أَشْتَرِيَهُ مِنْهُ وَظَنَنْتُ أَنَّهُ بَائِعُهُ بِرُخْصٍ فَسَأَلْتُ

عَنْ ذَلِكَ النَّبِيَّ ﷺ فَقَالَ لاَ تَشْتَرِهِ وَإِنْ أَعْطَاكَهُ بِدِرْهَمٍ وَاحِدٍ فَإِنَّ الْعَائِدَ فِي صَدَقَتِهِ كَالْكَلْبِ يَعُودُ فِي قَيْئِهِ  

ذِكْرُ الْبَيَانِ بِأَنَّ هَذَا الْفَرَسَ قَدْ ضَاعَ عِنْدَ الَّذِي كَانَ فِي يَدِهِ، فَأَرَادَ عُمَرُ أَنْ يَشْتَرِيَهُ بَعْدَ ذَلِكَ

ibnhibban:5125al-Ḥusayn b. Idrīs al-Anṣārī > Aḥmad b. Abū Bakr > Mālik > Zayd b. Aslam from his father > ʿUmar b. al-Khaṭṭāb

I gave a horse in Allah's Cause. The person to whom it was given, did not look after it. I intended to buy it from him, thinking that he would sell it cheap. When I asked the Prophet ﷺ he said, "Don't buy it, even if he gives it to you for one Dirham, as the person who takes back what he has given in charity, is like a dog that swallows back its vomit." (Using translation from Bukhārī 2623)  

ابن حبّان:٥١٢٥أَخْبَرَنَا الْحُسَيْنُ بْنُ إِدْرِيسَ الْأَنْصَارِيُّ قَالَ حَدَّثَنَا أَحْمَدُ بْنُ أَبِي بَكْرٍ عَنْ مَالِكٍ عَنْ زَيْدِ بْنِ أَسْلَمَ عَنْ أَبِيهِ أَنَّهُ قَالَ سَمِعْتُ عُمَرَ بْنَ الْخَطَّابِ يَقُولُ حَمَلْتُ عَلَى فَرَسٍ فِي سَبِيلِ اللَّهِ فَأَضَاعَهُ الَّذِي كَانَ عِنْدَهُ فَأَرَدْتُ أَنْ أَبْتَاعَهُ مِنْهُ وَظَنَنْتُ أَنَّهُ بَائِعُهُ بِرُخْصٍ فَسَأَلْتُ

عَنْ ذَلِكَ رَسُولَ اللَّهِ ﷺ فَقَالَ «لَا تَبْتَعْهُ وَإِنْ أَعْطَاكَهُ بِدِرْهَمٍ وَاحِدٍ فَإِنَّ الْعَائِدَ فِي صَدَقَتِهِ كَالْكَلْبِ يَعُودُ فِي قَيْئِهِ»