It is not permissible for the giver to buy the thing he gave to his brother. It was narrated that ‘Umar (may Allaah be pleased with him) said: I gave a horse to someone (to ride in jihad) for the sake of Allaah, and its owner neglected it. I thought that he would sell it cheaply, so I asked the Messenger of Allaah (peace and blessings of Allaah be upon him) about that, and he said: “Do not buy it, even if he gives it to you for a dirham, for the one who takes back his charity is like a dog that goes back to its vomit.”
And Allaah is the Source of strength.
