Is it permissible for a brother to retract his vow to his younger brother to grant him a plot of land, especially after he had pledged that to him, and unforeseen circumstances arose that made him realize that fulfilling the vow would affect his ability to pay his debts? And does the younger brother's selling of the plot of land without transferring ownership constitute selling what one does not own?

Disputes are to be referred to the judiciary, or the disputing parties should consult scholars. A gift becomes binding and valid the moment it is relinquished by the giver, and the lack of registration in the name of the donor does not affect its validity. The donor is not allowed to revoke their gift, based on the Prophet's (peace be upon him) sayings: "Do not go back on your charity," and "The one who revokes his gift is like a dog that returns to its vomit," and "It is not permissible for a man to give a gift or a donation and then revoke it, except for a father in what he gives to his child." His sale of the land is legally permissible.