Chapter 55: Wills and Testaments (Wasaayaa)
Narrated Ibn 'Umar: Once 'Umar gave a horse in charity to be used in holy fighting. It had been given to him by Allah' s
Apostle. 'Umar gave it to another man to ride. Then 'Umar was informed that the man put the horse
for sale, so he asked Allah' s Messenger (ﷺ) whether he could buy it. Allah' s Messenger (ﷺ) replied, "You should not
buy it, for you should not take back what you have given in charity."
Sahih al-Bukhari 2775