Art. 2115. The sale of the thing pledged shall extinguish the principal obligation, whether or not the proceeds of the sale are equal to the amount of the principal obligation, interest and  expenses  in  a  proper  case.  If  the  price  of  the  sale  is more than said amount, the debtor shall not be entitled to the excess, unless it is otherwise agreed. If the price of the sale is less, neither shall the creditor be entitled to recover the   deficiency,   notwithstanding   any   stipulation   to   the contrary. (n)

1.   If  the  price  of  the  sale  is  more  than  the  amount  due  the creditor, the debtor is not entitled to the excess unless the contrary is provided
2.   If the price of sale is less, neither is the creditor entitled to recover the deficiency
a.    The  reason  is  to  compel  the  creditor  to  hold  an honest public sale
b.   Creditor  should  realize  the  loans  only  as  much  as he is likely to realize at a public sale


> GENERAL  RULE—the  debtor  is  not  entitled  to  the  excess unless there is an agreement to the contrary
> To compensate the creditor for his risk of not being able to recover  the  deficiency  in  case  the  thing  pledged  is  sold below the amount of the principal obligation