legal ground
Article 394 of the Civil Code: In order to guarantee the performance of the debt, if the debtor or a third party does not transfer the possession of the property and mortgages the property to the creditor, if the debtor fails to perform the due debt or realize the mortgage right according to the agreement of the parties, the creditor has the right to be paid in priority for the property. The debtor or the third party specified in the preceding paragraph is the mortgagor, the creditor is the mortgagee, and the property provided as guarantee is the collateral.