Sahih al-Bukhari, 1489

Narrated `Abdullah bin `Umar:`Umar bin Al-Khattab gave a horse in charity in Allah's Cause and later he saw it being sold in the market and intended to purchase it. Then he went to the Prophet (ﷺ) and asked his permission. The Prophet said, "Do not take back what you have given in charity." For this reason, Ibn `Umar never purchased the things which he had given in charity, and in case he had purchased something (unknowingly) he would give it in charity again

Rapporté par `Abdullah bin `Umar : `Umar bin Al-Khattab a donné un cheval en aumône pour la cause d’Allah, puis il l’a vu vendu au marché et a voulu l’acheter. Il est alors allé demander la permission au Prophète (ﷺ). Le Prophète a dit : « Ne reprends pas ce que tu as donné en aumône. » Pour cette raison, Ibn `Umar n’a jamais racheté ce qu’il avait donné en aumône et, s’il achetait quelque chose (sans le savoir), il le donnait à nouveau en aumône