Arabic Text
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ عُمَرَ، بْنَ الْخَطَّابِ حَمَلَ عَلَى فَرَسٍ فِي سَبِيلِ اللَّهِ فَوَجَدَهُ يُبَاعُ فَأَرَادَ أَنْ يَبْتَاعَهُ فَسَأَلَ رَسُولَ اللَّهِ صلى الله عليه وسلم عَنْ ذَلِكَ فَقَالَ " لاَ تَبْتَعْهُ وَلاَ تَعُدْ فِي صَدَقَتِكَ " .
English Translation
Ibn 'Umar reported that 'Umar b. al-Khattib (Allah be pleased with him) donated a horse in the path of Allah and (later on) he found it being sold, and he decided to buy that. He asked the Messenger of Allah (ﷺ) about it. whereupon he (the Holy prophet) said: Don't buy that and do not get back what you gave in charity.
This hadith is from Sahih Muslim, one of the most rigorously authenticated collections in Islamic scholarship. No editorial opinion is added.