Buying a house is to sign a contract first and then borrow money from the bank. Buying a house loan is equivalent to setting a mortgage on the house bought by the bank. When the lender is unable to repay the bank's money, the bank can auction the mortgaged house and give priority to the proceeds from the auction to ensure that the bank's interests will not be lost. Therefore, before using the house to borrow money from the bank, you need to sign a house purchase contract first.