Salim reported from Ibn Umar (Allah be pleased with them) that 'Umar donated a horse in the path of Allah and then found it being sold, and he decided to buy that. He asked Allah's Apostle (ﷺ) about it, whereupon Allah's Messenger (ﷺ) said:Umar, do not get back what you gave as charity
Hadith No. 4169
Sahih Muslim