In the case of the vineyard taken by a creditor for 10 years, and the
vineyard became barren ("aged") after five years, he was allowed to revert to purchasers of land from his debtor to seize the land they purchased from the debtor subsequent to the date of the loan. The Gemara says "They caused the loss to themselves".
As far as I can see, the Gemara could equally have said about this creditor "He caused the loss to himself" in agreeing to have his loan repaid from a particular field, and shoulld not be allowed to revert to subsequent purchasers of land!
Thank you for your help.
A lender who accepts a "Mashkon," deposit for a loan, is actually doing a favor to the borrower, and does not relinquish his Shi'abud with it. Therefore, the later buyers lose for they should have known that there is a lien on the field they were purchasing.
D. Z.