he gave a horse in charity at the time of the Messenger of Allah ﷺ, then he saw its owner selling it for a low price. He went to the Prophet ﷺ and asked him about that, and he said: “Do not buy what you gave in charity.”  

أَنَّهُ تَصَدَّقَ بِفَرَسٍ عَلَى عَهْدِ رَسُولِ اللَّهِ ﷺ فَأَبْصَرَ صَاحِبَهَا يَبِيعُهَا بِكَسْرٍ فَأَتَى النَّبِيَّ ﷺ فَسَأَلَهُ عَنْ ذَلِكَ فَقَالَ لاَ تَبْتَعْ صَدَقَتَكَ  

he gave a horse called Ghamr or Ghamrah to someone, then he saw one of its colts or fillies attributed to his horse being sold, but he refrained from (buging) it.  

يُقَالُ لَهُ غَمْرٌ أَوْ غَمْرَةٌ فَرَأَى مُهْرًا أَوْ مُهْرَةً مِنْ أَفْلاَئِهَا يُبَاعُ يُنْسَبُ إِلَى فَرَسِهِ فَنَهَى عَنْهَا