Can a bank call on a customer to raise money elsewhere to reduce or replace their loans?

The second sentence of the present letter gives the bank the right to call on the customer to raise money elsewhere to. apply to – presumably in reduction of – his loans, or, alternatively, to provide “collateral mortgage security” for the loans. If the option is that of the borrower, rather than the bank, I do not think it can be said that the borrower has agreed to execute a mortgage when required or that his land shall stand as security. He has a right to do something else instead. In Mornington v. Kean (1858), 2 De G. & J. 292, 44 E.R. 1001 (L.C.), it was held that a covenant to secure an annuity in any of several ways creates no security.