What is the ruling on promising to sell a house on deferred payment, with the seller receiving the full price and the buyer receiving the house, and the buyer undertaking the expenses of transferring ownership and the price of the land, then the buyer delays paying the price of the land for 14 years, and the seller pays it, and then real estate prices rise? Is it permissible for the seller to reclaim the house and return the price to the buyer, or demand the difference in price or compensation, or not complete the sale?

If what transpired between the two parties was merely a promise to sell, then the seller may reclaim the sold item and return the price, or agree on a new price. However, if the sale was concluded and the procedures for transferring ownership were delayed, the seller is not permitted to demand an additional amount due to rising prices, because the buyer owned the property through a valid contract. In this case, the seller may annul the sale if the buyer does not fulfill the condition, or if it becomes impossible to obtain the price. If the expenses borne by the buyer are unknown, or if the sold item cannot be delivered at the time of the contract, then the contract is invalid.