The earthquake destroyed the house and needed to repay the loan. Because the purchase of commercial housing by mortgage loan involves two legal relationships: housing sale and mortgage loan. In the sale of housing, the developer is responsible for the delivery of housing, and the purchaser is responsible for paying the house price; In the mortgage loan, with the consent of the developer, the purchaser borrows from the bank with the commercial house to be purchased as collateral, and the obtained loan is used to pay the purchase price to the developer, and promises to repay as agreed. If the bank has fulfilled the loan obligation in accordance with the mortgage loan contract, then the buyer has the obligation to repay the loan in accordance with the agreement, and is not exempted from the obligation to repay the loan because of the damage or loss of the house.